The effect of crocin and safranal, constituents of saffron, against subacute effect of diazinon on hematological and genotoxicity indices in rats

In this study, the effect of crocin and safranal was studied against subacute toxicity of diazinon (DZN) on hematological and genotoxicity indices in rats. The rats were divided into 16 groups consisted of 6 rats in control, diazinon, vitamin E, vitamin E and DZN, crocin (3 doses), crocin (3 doses) and DZN, safranal (3 doses), safranal (3 doses) and DZN groups. Vitamin E (200 IU/kg), safranal at doses 0.025, 0.05 and 0.1 ml/kg and crocin at doses 50, 100 and 200 mg/kg were injected intraperitoneally to rats three times per week alone or with DZN (20 mg/kg/day, orally) for 4 weeks. Hematological parameters were evaluated at the end of 4 weeks. The evaluation of genotoxicity was done using the micronucleus assay. Vitamin E and, at lower doses, safranal (0.025 and 0.05 ml/kg) and crocin (50 mg/kg) restored the reduction of red blood cell, hemoglobin and hematocrit indices induced by DZN. These agents at some doses also prevented the reduction in platelets counts indices in diazinon treated group. A significant increase in reticulocyte was induced by diazinon. Vitamin E, safranal (0.025 or 0.05 ml/kg) and all doses of crocin decreased this effect of diazinon. In all doses vitamin E, crocin and safranal did not inhibit the effect of diazinon on RBC cholinesterase activity. A significant increase in micronucleus indices was seen with diazinon. Vitamin E, safranal and crocin could not prevent this genotoxicity. This study showed that vitamin E, safranal and crocin (without effects on cholinesterase) reduced diazinon hematological toxicity, but they did not prevent the genotoxicity induced by diazinon.     

Betaine (N,N,N-trimethylglycine) averts photochemically-induced thrombosis in pial microvessels in?vivo and platelet aggregation in?vitro

Betaine (N,N,N-trimethylglycine) is an important food component with established health benefits through its homocysteine-lowering effects, and is used to lower total homocysteine concentration in plasma of patients with homocystinuria. It is well established that hyperhomocysteinemia is an established risk factor for cardiovascular disease and stroke. However, the possible protective effect of betaine on coagulation events in vivo and in vitro has thus far not been studied. Betaine was given to mice at oral doses of either 10 mg/kg (n = 6) or 40 mg/kg (n = 6) for seven consecutive days, and control mice (n = 6) received water only. The thrombotic occlusion time in photochemically induced thrombosis in pial arterioles was significantly delayed in mice pretreated with betaine at doses of 10 mg/kg (P < 0.001) and 40 mg/kg (P < 0.01). Similar effects were observed in pial venules with 10 mg/kg (P < 0.05) and 40 mg/kg (P < 0.05) betaine. In vitro, in whole blood samples collected from untreated mice (n = 3–5), betaine (0.01–1 mg/mL) significantly reversed platelet aggregation induced by adenosine diphosphate (5 µM). The number of circulating platelets and plasma concentration of fibrinogen in vivo were not significantly affected by betaine pretreament compared with the control group. Lipid peroxidation (LPO) in mice pretreated with betaine was significantly reduced compared with the control group. Moreover, betaine (0.01–1 mg/mL) caused a dose-dependent and significant prolongation of PT (n = 5) and aPTT (n = 4–6). In conclusion, our data show that betaine protected against coagulation events in vivo and in vitro and decreased LPO in plasma.     

Pirfenidone alleviates cardiac fibrosis induced by pressure overload via inhibiting TGF‐β1/Smad3 signalling pathway

Cardiac fibrosis critically injured the cardiac structure and function of the hypertensive patients. However, the anti‐fibrotic strategy is still far from satisfaction. This study aims to determine the effect and mechanism of Pirfenidone (PFD), an anti‐lung fibrosis medicine, in the treatment of cardiac fibrosis and heart failure induced by pressure overload. Male C57BL/6 mice were subjected to thoracic aorta constriction (TAC) or sham surgery with the vehicle, PFD (300 mg/kg/day) or Captopril (CAP, 20 mg/kg/day). After 8 weeks of surgery, mice were tested by echocardiography, and then sacrificed followed by morphological and molecular biological analysis. Compared to the sham mice, TAC mice showed a remarkable cardiac hypertrophy, interstitial and perivascular fibrosis and resultant heart failure, which were reversed by PFD and CAP significantly. The enhanced cardiac expression of TGF‐β1 and phosphorylation of Smad3 in TAC mice were both restrained by PFD. Cardiac fibroblasts isolated from adult C57BL/6 mice were treated by Angiotensin II, which led to significant increases in cellular proliferation and levels of α‐SMA, vimentin, TGF‐β1 and phosphorylated TGF‐β receptor and Smad3. These changes were markedly inhibited by pre‐treatment of PFD. Collectively, PFD attenuates myocardial fibrosis and dysfunction induced by pressure overload via inhibiting the activation of TGF‐β1/Smad3 signalling pathway.     

Verapamil contributes to the clastogenic effects of acrylamide, cyclophosphamide, and dioxidine on somatic cells of BALB/C and C57BL/6 mice

The chromosome aberration assay of metaphase bone marrow cells was used to study the clastogenic effects of acrylamide, cyclophosphamide, dioxidine, and their combinations with Verapamil (a calcium antagonist) in male BALB/C and C57BL/6 mice. Verapamil gavage at single (5 mg/kg) and repeated doses (2.5 and 5 mg/kg five times at 24-h intervals) significantly enhanced the clastogenic activity of acrylamide (50 and 100 mg/kg intraperitoneally) in BALB/C mice; in C57BL/6 mice, this effect was only observed when they received Verapamil at doses of 2.5 mg/kg for 5 days. Verapamil administered repeatedly (2.5–10 mg, gavage) significantly increased the clastogenic activity of cyclophosphamide (10 mg/kg intraperitoneally) in C57BL/6 mice. In BALB/C mice, this effect of Verapamil was only observed at a dose of 10 mg/kg (gavage). When injected intraperitoneally at a single dose of 0.1–0.4 mg/kg, Verapamil significantly enhanced the clastogenic activity of cyclophosphamide in mice of both strains. This calcium antagonist produced identical effects when administered to BALB/C mice intraperitoneally (2.5 and 5 mg/kg) and by gavage (5 mg/kg) and to C57BL/6 mice intraperitoneally (5 and 10 mg/kg) and by gavage (2.5 mg/kg). Repeated administration of Verapamil (at all doses tested) promoted the clastogenic effect of dioxidine (100 mg/kg intraperitoneally) on C57BL/6 mice, having no such influence on BALB/C mice. These results demonstrate the co-clastogenic activity of Verapamil in mice and suggest that its specific manifestations depend on the dose, method, and route of drug administration and the genotype of test animals.     

Cognition enhancing abilities of vitamin D,epalrestat and their combination in diabetic rats with and without scopolamine induced amnesia

Persistent hyperglycaemia and scopolamine were used to inflict amnesia in rats. Chronic hyperglycaemia causes metabolic impairment, neuronal dysfunction and oxidative stress causing cognitive impairment. This study aimed to determine anti amnesic activities of vitamin D, epalrestat and their combination against diabetes and scopolamine induced cognitive dysfunction. A total of eighty-eight Wistar albino rats, eleven groups, and 8 rats/Gr., were used. Type 2 diabetes mellitus was induced in all groups, except Gr.1 which was treated with 2 ml normal saline. Gr. 2 to 11 by feeding high fat diet for 28 days followed by single dose streptozotocin 35 mg/kg i.p. Hyperglycemic rats were screened with blood sugar level > 200 mg/dL. Gr. 2 rats were treated with only streptozotocin and Gr. 3 to 6 were treated with streptozotocin and test drugs donepezil 1 mg/kg, vitamin D, 27 mcg/kg, epalrestat 57 mg/kg, vitamin D + epalrestat, per oral, respectively. Gr. 7 rats were treated with only streptozotocin + scopolamine and all others from Gr. 8 to 11 were treated with streptozotocin + scopolamine and donepezil, vitamin D, epalrestat, vitamin D + epalrestat respectively. The gold standard behavioural tests were conducted by using Morris water maze and passive avoidance paradigms after 30–60 min of inj. scopolamine, 0.5 mg/kg, intra-peritoneal. Hippocampal tissue was taken for histopathological and biochemical evaluation. Rats treated with donepezil, vitamin D, epalrestat and vitamin D + epalrestat showed significant improvement in behavioural, biochemical and histopathological parameters as compared to streptozotocin and (streptozotocin + scopolamine) treated rats. This study underscores cognition enhancing abilities of vitamin D and epalrestat, and their combination in diabetic rats with and without scopolamine.     

Assessment of pharmacological activities of two medicinal plant of Bangladesh: Launaea sarmentosa and Aegialitis rotundifolia roxb in the management of pain,pyrexia and inflammation

Background

The current study aims at evaluating the analgesic, anti-pyretic and anti-inflammatory properties of methanolic extract of the stem, bark and leaves of Launaea sarmentosa and Aegialitis rotundifolia roxb.

Results

The AELS and AEAR extract presented a significant (***p < 0.001) dose dependent increase in reaction time in writhing method and showed inhibition of 63.1% and 57.1% respectively at the doses of 400 mg/kg body weight while standard drug showed (P < 0.001) inhibition of 69.23%. In tail immersion method, AELS and AEAR showed maximum time of tail retention at 30 min in hot water i.e. 6.93 sec and 6.54 sec respectively at highest doses of 400 mg/kg body weight than lower dose while standard pentazocine showed reaction time of 7.62 sec. The AELS and AEAR extract also exhibited promising anti-inflammatory effect as demonstrated by statistically significant inhibition of paw volume by 32.48% and 26.75% respectively at the dose of 400 mg/kg body weight while the value at the dose of 200 mg/kg body weight were linear to higher dose at the 3^rd hour of study. On the other hand, Standard indomethacin inhibited 40.13% of inflammation (***P < 0.001). In Cotton-pellet granuloma method, AELS and AEAR extract at the dose of 400 mg/kg body weight exhibited inhibition of inflammation of 34.7% and 29.1% respectively while standard drug showed (P < 0.001) inhibition of 63.22%. Intraperitoneal administration of AELS and AEAR showed dose dependent decrease in body temperature in brewer’s yeast induced hyperthermia in rats at both doses. However, AELS significantly decreased body temperature (***p < 0.001) at 400 mg/kg compared to control.

Conclusions

Present work propose that the methanolic extract of Launaea sarmentosa and Aegialitis rotundifolia roxb possesses dose dependent pharmacological action which supports its therapeutic use in folk medicine possibly mediated through the inhibition or blocking of release of prostaglandin and/or actions of vasoactive substances such as histamine, serotonin and kinins.     

Antioxidant effect of selenium on lipid peroxidation,hyperlipidemia and biochemical parameters in rats exposed to diazinon

Diazinon (DZN) is one of the most organophosphate insecticides that widely used in agriculture and industry. Selenium is generally recognized to be a trace mineral of great importance for human health, protecting the cells from the harmful effects of free radicals. Therefore, the present study was carried out to investigate the alterations in biochemical parameters, free radicals and enzyme activities induced by diazinon in male rat serum, and the role of selenium in alleviating the negative effects of DZN. Animals were divided into four groups of seven rats each; the first group was used as control. Groups 2, 3 and 4 were treated with selenium (Se; 200 μg/kg BW), diazinon (DZN; 10 mg/kg BW) and diazinon plus selenium, respectively. Rats were orally administered their respective doses daily for 30 days. Results obtained showed that DZN significantly induced thiobarbituric acid reactive substances (TBARS) and decreased the activities of glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) and the levels of reduced glutathione (GSH) in rat sera. Aminotransferases (AST, ALT), phosphatases (AlP, AcP) and lactate dehydrogenase (LDH) activities were significantly increased while acetylcholinesterase (AChE) activity was decreased due to DZN administration. Also, DZN treatment caused significant perturbations in lipids profile and serum biochemical parameters. On the other hand, Se alone significantly decreased the levels of TBARS, total lipids, cholesterol, urea and creatinine, while increased the activities of antioxidant enzymes and glutathione content, total protein (TP) and albumin. In addition, Se in combination with DZN partially or totally alleviated its toxic effects on the studied parameters. In conclusion, Se has beneficial effects and could be able to antagonize DZN toxicity.     

In vivo analgesic,antipyretic, and anti-inflammatory potential in Swiss albino mice and in vitro thrombolytic activity of hydroalcoholic extract from Litsea glutinosa leaves

Background

The study was conducted to evaluate the in vitro thrombolytic activity, and in vivo analgesic, anti-inflammatory and antipyretic potentials of different hydrocarbon soluble extracts of Litsea glutinosa leaves for the first time widely used in the folkloric treatments in Bangladesh. This work aimed to create new insights on the fundamental mechanisms of the plant extracts involved in these activities.

Results

In thrombolytic activity assay, a significant clot disruption was observed at dose of 1 mg/mL for each of the extracts (volume 100 μL) when compared to the standard drug streptokinase. The n-hexane, ethyl acetate, chloroform, and crude methanolic extracts showed 32.23 ± 0.26, 37.67 ± 1.31, 43.13 ± 0.85, and 46.78 ± 0.9% clot lysis, respectively, whereas the positive control streptokinase showed 93.35 ± 0.35% disruption at the dose of 30,000 I.U. In hot plate method, the highest pain inhibitory activity was found at a dose of 500 mg/kg of crude extract (15.54 ± 0.37 sec) which differed significantly (P <0.01 and P <0.001) with that of the standard drug ketorolac (16.38 ± 0.27 sec). In acetic acid induced writhing test, the crude methanolic extract showed significant (P <0.01 and P <0.001) analgesic potential at doses 250 and 500 mg/kg body weight (45.98 and 56.32% inhibition, respectively), where ketorolac showed 64.36% inhibition. In anti-inflammatory activity test, the crude methanolic extract showed significant (P <0.001) potential at doses 250 and 500 mg/kg body weight (1.51 ± 0.04 and 1.47 ± 0.03 mm paw edema, respectively), where ketorolac showed 1.64 ± 0.05 mm edema after 3 h of carrageenan injection. In antipyretic activity assay, the crude extract showed notable reduction in body temperature (32.78 ± 0.46°C) at dose of 500 mg/kg-body weight, when the standard (at dose 150 mg/kg-body weight) exerted 33.32 ± 0.67°C temperature after 3 h of administration.

Conclusions

Our results yield that the crude hydroalcoholic extract has better effects than the other in all trials. In the context, it can be said that the leaves of L. glutinosa possess remarkable pharmacological effects, and justify its traditional use as analgesic, antipyretic, anti-inflammatory, and thrombolytic agent.     

New Insights into the Methodology of L-Arginine-Induced Acute Pancreatitis

Animal models are ideal to study the pathomechanism and therapy of acute pancreatitis (AP). The use of L-arginine-induced AP model is nowadays becoming increasingly popular in mice. However, carefully looking through the literature, marked differences in disease severity could be observed. In fact, while setting up the L-arginine (2×4 g/kg i.p.)-induced AP model in BALB/c mice, we found a relatively low rate (around 15%) of pancreatic necrosis, whereas others have detected much higher rates (up to 55%). We suspected that this may be due to differences between mouse strains. We administered various concentrations (5–30%, pH = 7.4) and doses (2×4, 3×3, or 4×2.5 g/kg) of L-arginine-HCl in BALB/c, FVB/n and C57BL/6 mice. The potential gender-specific effect of L-arginine was investigated in C57BL/6 mice. The fate of mice in response to the i.p. injections of L arginine followed one of three courses. Some mice (1) developed severe AP or (2) remained AP-free by 72 h, whereas others (3) had to be euthanized (to avoid their death, which was caused by the high dose of L-arginine and not AP) within 12 h., In FVB/n and C57BL/6 mice, the pancreatic necrosis rate (about 50%) was significantly higher than that observed in BALB/c mice using 2×4 g/kg 10% L–arginine, but euthanasia was necessary in a large proportion of animals, The i.p. injection of lower L-arginine concentrations (e.g. 5–8%) in case of the 2×4 g/kg dose, or other L-arginine doses (3×3 or 4×2.5 g/kg, 10%) were better for inducing AP. We could not detect any significant differences between the AP severity of male and female mice. Taken together, when setting up the L-arginine-induced AP model, there are several important factors that are worth consideration such as the dose and concentration of the administered L arginine-HCl solution and also the strain of mice.     

Prophylactic effect of vitamin E against hepatotoxicity,nephrotoxicity, haematological indices and histopathology induced by diazinon insecticide in mice

Considering that the involvement of reactive oxygen species(ROS)has been implicated in the toxicity of various pesticides,this study was designed to study the ameliorative effect of Vitamin E(100 mg/kg body weight)on mice(25-30 mg)treated with diazinon(32.5 or 16.25 mg/kg body weight)organophosphate insecticide for 14 days.Subchronic DZN exposure and the protective effects of vitamins E(vitE)were evaluated for their effects on haematological indices,the enzymes concerning liver damage [plasma alanine aminot...     

Pigment epithelium-derived factor expression prolongs survival and enhances the cytotoxicity of low-dose chemotherapy in castration-refractory prostate cancer

There is currently no cure for advanced castration-refractory prostate cancer (CRPC) despite the recent approval of several new therapeutic agents. We report here the anti-tumor effect of the angio-inhibitory pigment epithelium-derived factor (PEDF) in the metastatic LNCaP-derivative CRPC CL1 model and explore PEDF anti-neoplasic efficacy in combination with low-dose chemotherapy. Androgen-sensitive LNCaP and CRPC PC3 cell lines were examined as comparison. Using a retroviral expression system, we showed that PEDF limited the proliferation of all prostatic cell lines tested; an effect attributed to interleukin 8 (IL8)-CXCR1/IL8RA inhibition. PEDF also reduced the number and size of 3D tumor spheroids in vitro, but only induced cell differentiation in CRPC spheroids. Similarly, PEDF inhibited the migration of CRPC cells suggesting both anti-proliferative and anti-migratory functions. In vivo, PEDF decreased by 85% and 65% the growth of subcutaneous (s.c.) PC3 and CL1 tumors, respectively. In the CL1 orthotopic model, tumor intake with lethal metastases was found in all animals; nevertheless, PEDF prolonged the median survival of tumor-bearing mice (95% confidence interval: 53±0.001 to 57±1 days). Accordingly, PEDF delayed the emergence of skeletal-related event in intra-tibial xenografts. Next, we evaluated low-dose docetaxel (DTX; 5, 1, 0.5 mg/kg) or cyclophosphamide (CTX; 10–20 mg/kg) on established s.c. PC3 tumors that conditionally express PEDF anti-tumoral epitope/NT3. Although NT3–DTX-5 mg/kg combination was inefficient, NT3–DTX-1 mg/kg and -0.5 mg/kg inhibited by 95% and 87.8%, respectively, tumor growth compared with control and induced tumor stasis. Both NT3–CTX combinations were advantageous. Inversely, PEDF–DTX-5 mg/kg and PEDF–CTX-10 mg/kg delayed the most CL1 tumor growth (15, 11 and 5 days for PEDF–DTX-5 mg/kg, PEDF–CTX-10 mg/kg and single treatments, respectively) with elevated apoptosis and serum thrombospondin-1 as possible mechanism and marker, respectively. As well, both PEDF–CTX-10 mg/kg and PEDF–DTX-5 mg/kg prolonged significantly the survival of tumor-bearing mice compared with single treatments. Metastases were reduced in PEDF–DTX-5 mg/kg compared with other treatments, suggesting that PEDF–DTX delayed metastases formation. Our results advocate that PEDF/low-dose chemotherapy may represent a new therapeutic alternative for CRPC.     

A Pilot Study to Examine the Effect of Chronic Treatment with Immunosuppressive Drugs on Mucociliary Clearance in a Vagotomized Murine Model

Background

Previously, we have demonstrated that mucociliary clearance (MCC) is diminished within the first months after surgery in lung transplant patients and the explanation for the reduction in MCC is unknown. We hypothesized that chronic treatment with a commonly prescribed regimen of immunosuppressive drugs significantly impairs MCC. We tested this hypothesis in a murine model of lung transplantation.

Methods

Fifteen C57BL/6 mice underwent vagotomy on the right side to simulate denervation associated with lung transplantation in humans. For 6 days, seven mice (controls) were intraperitoneally injected with three 100 µL doses of phosphate buffered saline and eight mice (immunosuppressed) were injected with three 100 µL injections of tacrolimus (1 mg/kg), mycophenolate mofetil (30 mg/kg), and prednisone (2 mg/kg) once daily. Then, mice inhaled the radioisotope ^99mtechnetium and underwent gamma camera imaging of their lungs for 6.5 hrs. Counts in the right lung at 1–1.5 hrs and at 6–6.5 hrs were first background-corrected and then decay-corrected to time 0 counts. Decay-corrected counts were then divided by time 0 counts. Retention at each time point was subtracted from 1.00 and multiplied by 100% to obtain percent removed by mucociliary clearance.

Results

Although there was a slowing of MCC at 1–1.5 hrs for the immunosuppressed mice, there was no statistical difference in MCC measured at 1–1.5 hrs for the two groups of mice. At 6–6.5 hrs, MCC was significantly slower in the immunosuppressed mice, compared to controls, with 7.78±5.9% cleared versus 23.01±11.7% cleared, respectively (p = 0.006).

Conclusions

These preliminary results suggest that chronic treatment with immunosuppressive medications significantly slows MCC in vagotomized C57BL/6 mice. These findings could shed light on why MCC is reduced in lung transplant patients whose lungs are denervated during surgery and who are chronically treated with immunosuppressive drugs post surgery.     

Losartan reduces oxidative damage to renal DNA and conserves plasma antioxidant capacity in diabetic rats

Increased reactive oxygen species (ROS) levels produced by hyperglycemia and angiotensin-II (AT-II) are considered among the pathogenic factors in the malignant transformation of diabetic renal cells. We aimed to investigate the potential role of AT-II in the increased cancer risk seen in diabetes; measuring oxidative damage to renal DNA and protective antioxidant defenses, including adiponectin (Adp) and plasma antioxidant capacity by the Ferric Reducing Ability of Plasma (FRAP) method. In the kidney of streptozotocin (STZ)-induced (55 mg/kg) diabetic rats either treated or not treated for 3 weeks with losartan, an AT-II type 1 receptor antagonist (20 mg/kg/day); we measured 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) levels, as an index of oxidative DNA damage, circulating Adp and FRAP. Diabetic rats showed significantly higher 8-oxodGuo levels in renal DNA (8.48 ± 0.98 × 10⁻⁶ dG, mean ± SEM n = 11) than normoglycemic ones (1.18 ± 0.04 × 10⁻⁶ dG, mean ± SEM, n=7) and lower plasma Adp and FRAP levels in comparison to normoglycemics. The treatment of diabetic rats with losartan significantly (P < 0.01) reduced 8-oxodGuo levels (5.4 ± 0.58 × 10⁻⁶ dG, mean ± SEM n=9) in renal DNA and conserved FRAP values. Moreover, an inverse correlation was found between 8-oxodGuo in kidney DNA and circulating Adp levels in normoglycemic and diabetic rats. Losartan treatment preserves FRAP levels, reduces DNA oxidative injury and thus the carcinogenesis risk. Furthermore, our results indicate that Adp plasma levels are a further marker of oxidative injury to the kidney and confirm that it is an important part of the plasma antioxidant defense.     

Epigallocatechin-3-gallate protects against cisplatin-induced nephrotoxicity by inhibiting endoplasmic reticulum stress-induced apoptosis

Cisplatin (CP)-induced nephrotoxicity hampers its application in clinic. Green tea, particularly its predominant polyphenolic constituent epigallocatechin-3-gallate (EGCG), possesses anti-inflammatory, antioxidant, and anti-apoptotic properties. The present study was designed to investigate the protective effects of EGCG against CP-induced nephrotoxicity in mice. Male C57/BL6 mice in different groups received single injection of CP (20 mg/kg) and EGCG (100 mg/kg) in various sets and kidney tissues and blood were collected after killing. Then, samples were used for biochemical and immunohistochemical assay. Our results showed EGCG decreased biochemical factors and immunohistochemical damage induced by CP. Besides, expression of phosphorylated-extracellular signal-regulated kinase (p-ERK), glucose-regulated protein 78 (GRP78), caspase-12, and apoptosis of kidney were decreased by EGCG via inhibition of endoplasmic reticulum (ER) stress-induced apoptosis.     

Effect of Delta-9-Tetrahydrocannabinol on Mouse Resistance to Systemic Candida albicans Infection

Delta-9-tetrahydrocannabinol (Δ⁹-THC), the psychoactive component of marijuana, is known to suppress the immune responses to bacterial, viral and protozoan infections, but its effects on fungal infections have not been studied. Therefore, we investigated the effects of chronic Δ⁹-THC treatment on mouse resistance to systemic Candida albicans (C. albicans) infection. To determine the outcome of chronic Δ⁹-THC treatment on primary, acute systemic candidiasis, c57BL/6 mice were given vehicle or Δ⁹-THC (16 mg/kg) in vehicle on days 1–4, 8–11 and 15–18. On day 19, mice were infected with 5×10⁵ C. albicans. We also determined the effect of chronic Δ⁹-THC (4–64 mg/kg) treatment on mice infected with a non-lethal dose of 7.5×10⁴ C. albicans on day 2, followed by a higher challenge with 5×10⁵ C. albicans on day 19. Mouse resistance to the infection was assessed by survival and tissue fungal load. Serum cytokine levels were determine to evaluate the immune responses. In the acute infection, chronic Δ⁹-THC treatment had no effect on mouse survival or tissue fungal load when compared to vehicle treated mice. However, Δ⁹-THC significantly suppressed IL-12p70 and IL-12p40 as well as marginally suppressed IL-17 versus vehicle treated mice. In comparison, when mice were given a secondary yeast infection, Δ⁹-THC significantly decreased survival, increased tissue fungal burden and suppressed serum IFN-γ and IL-12p40 levels compared to vehicle treated mice. The data showed that chronic Δ⁹-THC treatment decreased the efficacy of the memory immune response to candida infection, which correlated with a decrease in IFN-γ that was only observed after the secondary candida challenge.     

Imatinib activity on Schistosoma mansoni

Imatinib, a drug used for treatment of human chronic myeloid leukaemia, due to its activity against protein kinases, has been also evaluated in vitro against Schistosoma mansoni showing high schistosomicidal activity. In the present experiments imatinib activity in vitro was confirmed at the doses of 25 µM, 50 µM and 100 µM. The first drug activity observed with the lower dose was interruption of egg-laying and with the higher dosages was the death of the worms. In mice infected with S. mansoni no activity was found even with 1,000 mg/kg/day, 500 mg/kg/day, single oral dose or when administered for three consecutive days. This is another example of the difference of results related to in vitro and in vivo trials using S. mansoni worms.     

Role of natural killer cells in the modulation of primary antibody production by purine nucleosides and their analogs.

Previous results from this laboratory demonstrated that treatment of mice with the adenosine analog tubercidin (Tub) reduced natural killer (NK) cell activity while stimulating antibody production whereas the deoxyadenosine analog, 2-fluoroadenine arabinoside-5'-monophosphate (FaraAMP), produced opposite effects; i.e., it stimulated NK cell activity at doses that inhibited antibody formation (Cancer Res. 48, 4799, 1988). Since NK cells have been reported to play a suppressor role in immunoglobulin induction, it was hypothesized that the actions of Tub and FaraAMP on antibody production occurred secondary to their opposing effects on NK cells. To test this hypothesis, abilities of these nucleoside analogs to modulate primary antibody response to sheep red blood cells were evaluated in a C57BL/6 mutant mouse lacking NK cell activity (the beige mutation. C57BL/6-bg/bg). As previously found with C3H/He mice. NK cell activity was inhibited (Tub, doses 2-6 mg/kg/day for 3 days) or stimulated (FaraAMP, doses 75-250 mg/kg/day for 3 days) in heterozygous mice C57BL/6-bg/+. In support of the hypothesis, these nucleosides had no effect on primary antibody formation in the homozygous mutant mice at doses that clearly stimulated (Tub) or inhibited (FaraAMP) this immune response in heterozygous C57BL/6-bg/+ animals. This results was corroborated in C57BL/6 wild-type mice by abrogation of NK cell activity using a monoclonal antibody to the NK cell surface glycophisingolipid, ganglio-n-tetraosylceramide. We conclude that under the conditions of drug administration, modulation of primary antibody formation by Tub and FaraAMP in mice occurs indirectly via NK cells. Similar experiments using the potent ADA inhibitor, deoxycoformycin, indicated that its enhancement of primary antibody formation is independent of NK cell activity.     

Activation of Src-dependent Smad3 signaling mediates the neutrophilic inflammation and oxidative stress in hyperoxia-augmented ventilator-induced lung injury

Background

Mechanical ventilation and concomitant administration of hyperoxia in patients with acute respiratory distress syndrome can damage the alveolar epithelial and capillary endothelial barrier by producing inflammatory cytokines and reactive oxygen species. The Src tyrosine kinase and Smad3 are crucial inflammatory regulators used for ventilator-induced lung injury (VILI). The mechanisms regulating interactions between high-tidal-volume mechanical ventilation, hyperoxia, and acute lung injury (ALI) are unclear. We hypothesized that high-tidal-volume mechanical stretches and hyperoxia augment lung inflammation through upregulation of the Src and Smad3 pathways.

Methods

Wild-type or Src-deficient C57BL/6 mice, aged between 6 and 8 weeks, were exposed to high-tidal-volume (30 mL/kg) ventilation with room air or hyperoxia for 1–4 h after 2-mg/kg Smad3 inhibitor (SIS3) administration. Nonventilated mice were used as control subjects.

Results

We observed that the addition of hyperoxia to high-tidal-volume mechanical ventilation further induced microvascular permeability, neutrophil infiltration, macrophage inflammatory protein-2 and matrix metalloproteinase-9 (MMP-9) production, malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase activity, MMP-9 mRNA expression, hypoxemia, and Src and Smad3 activation (P < 0.05). Hyperoxia-induced augmentation of VILI was attenuated in Src-deficient mice and mice with pharmacological inhibition of Smad3 activity by SIS3 (P < 0.05). Mechanical ventilation of Src-deficient mice with hyperoxia further reduced the activation of Smad3.

Conclusions

Our data suggest that hyperoxia-increased high-tidal-volume ventilation-induced ALI partially depends on the Src and Smad3 pathways.     

Acute oral toxicity and anti-inflammatory activity of hydroalcoholic extract from Lampaya medicinalis Phil in rats

Background

Algesia and inflammation are related with several pathological conditions. It is known that many drugs available for the treatment of these problems cause unwanted side effects. This study was aimed at evaluating acute toxicity and anti-inflammatory activity of Lampaya medicinalis Phil. (Verbenaceae) widely used in the folk medicine of Northern Chile against rheumatism, arthritis and body joints pain.

Results

Oral administration of hydroalcoholic extract (HAE) at the highest dose of 3000 mg/ Kg body weight resulted in no mortalities or evidence of significant behavioral changes. Histological examination revealed normal architecture and no significant adverse effects were observed on the liver, kidney, heart, lung or ovaries and testicles. The results suggest that the oral administration of hydroalcoholic extract (HAE) from Lampaya medicinalis did not produce any toxic effect in rats. Hydroalcoholic extract (HAE) significantly inhibited the carrageenan-induced rat paw edema in dose – response relationship, at test doses of 37.5, 75, 150 and 300 mg/Kg body weight. Maximum inhibition (61.98 ± 2.69%) was noted at 300 mg/Kg after 2 h of drug treatment carrageenan induced paw edema, whereas indomethacin produced 47.90 ± 1.16% of inhibition. The inhibitory values of edema at 3 h postcarrageenan were 31.04±0.75%, 40.51 ± 2.36%, 48.97 ± 1.14% and 56.87 ± 0.41% for 37.5, 75, 150, and 300 mg/kg of extract respectively. Indomethacin (10 mg/Kg) gave a percentage inhibition of 49.44 ± 1.44. HAE (300 and 150 mg/kg) induced an anti-inflammatory effect greater than (or comparable) with the effect of indomethacin from 2nd to 4th hours of the experiment.

Conclusions

Our results reveal for first time that compounds contained in the hydroalcoholic extract of Lampaya medicinalis Phil exert anti-inflammatory effect and the oral administration is safe and non toxic up to dose level 3000 mg/kg body weight. The anti-inflammatory activity may be associated with the presence of flavonoids. These findings also justify the traditional use of the plant for treating pain.     

The liver X receptor agonist TO901317 protects mice against cisplatin-induced kidney injury

Liver X receptors are in the nuclear receptor superfamily and are contained in the regulation of lipid and cholesterol metabolism. Besides, liver X receptors are considered crucial regulators of the inflammatory response and innate immunity. The current study evaluates the in vivo effects that the synthetic liver X receptor agonist TO901317 protects against cisplatin-induced kidney injury in mice. Mice received cisplatin administration through a single intraperitoneal injection (20 mg/kg in saline). And then the mice were treated with the TO901317 by daily gavage (10 mg/kg/day) 12 h postcisplatin administration, and cisplatin nephrotoxicity was evaluated. At 72 h after cisplatin treatment, elevated plasma urea and creatinine levels (P < 0.05) were evidenced which indicates the renal dysfunction of the vehicle-treated mice, consistent with tubular necrosis, protein cast, dilation of renal tubules, and desquamation of epithelial cells in renal tubules. In contrast, the severity of renal dysfunction and histological damage was reduced in TO901317 treated mice (P < 0.05). In accordance, circulating tumor necrosis factor alpha levels, renal tumor necrosis factor alpha, p47^phox, gp91^phox, and protein expression levels and COX-2 mRNA, renal monocyte chemoattractant protein 1, VACAM-1 mRNA and intercellular adhesion molecule-1 contents, and renal prostaglandin E₂ amounts, were higher in samples from cisplatin-treated mice in comparison with controls (P < 0.05) but attenuated in the TO901317 treatment group (P < 0.05). Taken together, treatment with the liver X receptor agonist TO901317 ameliorated the inflammatory response and oxidative stress in cisplatin-induced kidney injury in mice.