The modulating effects of tumor necrosis factor alpha antibody on ricin-induced oxidative stress in mice

Previous studies in our laboratory have shown that the protein toxin ricin induces an oxidative stress in mice, resulting in increased urinary excretion of malondialdehyde (MDA), formaldehyde (FA), and acetone (ACON). Other toxicants have been shown to induce oxidative stress by macrophage activation with subsequent release of reactive oxygen species and tumor necrosis factor alpha (TNF-α). Therefore, the ability of TNF-α antibody to modulate ricin-induced urinary carbonyl excretion as well as hepatic lipid peroxidation, glutathione depletion, and DNA single-strand breaks was assessed. Ricin-induced urinary MDA, FA, and ACON were reduced significantly in mice receiving antibody (15,000 U/kg) 2 hours before treatment with ricin (5 μ/kg). At 48 hours following ricin treatment, MDA, FA, and ACON concentrations in the urine of TNF antibody-treated mice decreased 25.7, 53.2, and 64.5%, respectively, relative to ricin-treated mice receiving no antibody. In addition, anti-TNF-α (1500 U/kg) significantly decreased hepatic lipid peroxidation and DNA single-strand breaks, induced by 5 μg ricin/kg, by 49.3 and 44.2%, respectively. The results suggest that macrophage activation and subsequent release of TNF-α are involved in ricin toxicity.     

Dual role of polymorphonuclear neutrophils on the growth of Ehrlich ascites tumor (EAT) in mice

We show that granulocytes (PMN) have a dual role in the development of Ehrlich Ascites Tumor (EAT) in mice. EAT intraperitoneal inoculation causes a local inflammatory reaction, ascites development and mortality that distinguish resistant and susceptible strains. In resistant mice (CAF1), there is a less pronounced PMN influx after EAT inoculation than in susceptible Swiss mice. Accordingly, the increase in peritoneal PMN numbers enhanced tumor growth in CAF1 mice, but had no effect in the susceptible Swiss animals. Contrastingly, PMN depletion had no effect in resistant mice but facilitated tumor growth in susceptible animals. Though no differences were noted between the strains in peritoneal cell spreading and hydrogen peroxide release after tumor inoculation, in vitro PMN cytotoxic activity against EAT was significantly higher in susceptible Swiss mice. These data indicate a paradoxical dual role for PMN against EAT: while they help control tumor development in susceptible animals, they seem to enhance tumor growth in resistant mice.     

Comparison of the biodistribution of free or liposome-entrapped Crotalus durissus terrificus (South American rattlesnake) venom in mice

The local absorption rate, clearance and tissue distribution of Crotalus durissus terrificus venom, (Cdt) were examined using a two-antibody sandwich ELISA assay. We compared the biodistribution of both free or encapsulated Cdt in mice. Following subcutaneous injection of 10 microg/mouse of free Cdt (0.8 LD50), venom was detected in serum after 15 min, showed its highest level at 30 min (45+/-5 ng/ml) and was cleared from the circulation after 6 h. After 2 h of inoculation, venom was detected in the kidney (57+/-9 ng/g of tissue), spleen (18+/-4 ng/g of tissue) and brain (14+/-6 ng/g of tissue). For both subcutaneous or intravenous injection of free Cdt, venom was firstly detected in the kidney. No Cdt appeared either in the kidney, spleen, brain, or other tissues after subcutaneous inoculation of encapsulated venom even though a higher dose was used, 25 microg/mouse (2 LD50). Venom remained at the site of injection for a period of 1 week. Following intravenous injection of encapsulated venom (5 microg/mouse, 2 LD50), venom was detected in liver and spleen tissues. The biodistribution of encapsulated venom is discussed in relation to the effects of reduction of toxicity and increase of adjuvanticity.     

Hyperalgesic and edematogenic effects of Secapin-2, a peptide isolated from Africanized honeybee (Apis mellifera) venom

Honeybee stings are a severe public health problem. Bee venom contains a series of active components, including enzymes, peptides, and biogenic amines. The local reactions observed after envenoming include a typical inflammatory response and pain. Honeybee venom contains some well-known polycationic peptides, such as Melittin, Apamin, MCD peptide, Cardiopep, and Tertiapin. Secapin in honeybee venom was described 38 years ago, yet almost nothing is known about its action. A novel, variant form of this peptide was isolated from the venom of Africanized honeybees (Apis mellifera). This novel peptide, named Secapin-2, is 25 amino acid residues long. Conformational analyses using circular dichroism and molecular dynamics simulations revealed a secondary structure rich in strands and turns, stabilized by an intramolecular disulfide bridge. Biological assays indicated that Secapin-2 did not induce hemolysis, mast cell degranulation or chemotactic activities. However, Secapin-2 caused potent dose-related hyperalgesic and edematogenic responses in experimental animals. To evaluate the roles of prostanoids and lipid mediators in the hyperalgesia and edema induced by this peptide, Indomethacin and Zileuton were used to inhibit the cyclooxygenase and lipoxygenase pathways, respectively. The results showed that Zileuton partially blocked the hyperalgesia induced by Secapin-2 and decreased the edematogenic response. In contrast, Indomethacin did not interfere with these phenomena. Zafirlukast, a leukotriene receptor antagonist, blocked the Secapin-2 induced hyperalgesia and edematogenic response. These results indicate that Secapin-2 induces inflammation and pain through the lipoxygenase pathway in both phenomena.     

大胡蜂蜂毒中多肽和蛋白质结构和功能的多样性

为证明大胡蜂Vespa magnifica(Smith)蜂毒具有较大的药用开发价值,本研究采用超高效液相色谱-质谱和电泳技术对其多肽和蛋白质的分布进行分析,发现其蛋白质的相对分子质量主要分布在17~45kDa范围内。蜂毒多肽类物质的相对分子质量呈"单峰"式分布,61%在500~3000Da范围内,为大胡蜂蜂毒中多肽含量最为丰富的部分。通过牛津杯法对蜂毒的抑菌活性进行研究,且以HepG2人肝癌细胞及B16黑色素瘤细胞为研究对象,用MTT法检测蜂毒的细胞毒性活性,证明其具有良好的抑菌作用和细胞毒活性,其结果与已报道的其他蜂类既有相似性又存在具体差异,展示了大胡蜂蜂毒的分子多样性,为后续该毒素的物质基础研究及药用价值开发提供参考。     

Effect of food deprivation on oxidative stress biomarkers in fish (Sparus aurata)

Oxidative stress in fish (Sparus aurata) as a consequence of food restriction and fasting, has been studied. Four groups of fish were maintained for 46 days under different conditions of food supplementation: a control group with no food restriction (ratio of food/fish of 2% w/w), two groups of animals with restricted food supplement (1 and 0.5%) and a fasting group (no meal addition). Finally, all the fish were provided with food at the same ratio as the control group for the last 7 days. Sampling and weighing of fish were carried out every week and their livers were used for the analysis of known biomarkers of oxidative stress. Malondialdehyde and oxidized glutathione levels increased at the third week in fish with partial or total food deprivation, but these levels returned to normal values when the fish readapted to the control conditions. Antioxidant enzymes were also analyzed and significant increases in superoxide dismutase (SOD), glutathione reductase and glutathione peroxidase activities were found in parallel with food restriction; however catalase activity decreased in fasting fish. New SOD isoforms were detected by isoelectrofocusing in fish under food restriction at the second week, which disappeared when starved fish returned to the control conditions. These new SOD isoforms were detected before the appearance of other usual oxidative stress biomarkers.     

Melatonin effect on the ultrastructure of Ehrlich ascites tumor cells,lifetime and histopathology in Swiss mice

Aims

One of the models used for studying cancer is the Ehrlich ascites tumor (EAT) due to its ability to grow in liquid suspension, allowing a standard number of cells to be inoculated, growth quantification and regression of tumor mass. Among the oncostatic substances, melatonin has shown effectiveness in limiting the tumor cell proliferation. However, studies have shown contradictory effects of melatonin on the EAT. This study has investigated the melatonin effect on tumor growth, time and survival percentage, ultrastructure and metastasis of EAT cells in mice submitted or not to pinealectomy.

Main methods

Animals were inoculated with 5 × 10⁶ cells/mL and treated or not with exogenous melatonin with doses of at 150 and 300 μg/30 g animal weight for 12 days. Melatonin significantly reduced the abdominal circumference, volume of ascites liquid and EAT-cell viability, raising rates of time and mice survival percentage.

Key findings

Ultrastructurally, the melatonin treatment revealed changes in the shape of cells, the cell surface showed numerous projections, some bifurcated, cytoplasmic vacuolation, mitochondrial degeneration and nuclear fragmentation, peculiar characteristics of apoptosis. Histopathology revealed no metastasis in the liver, small intestine and large intestine in any of the animals in the experimental groups; however this process was evident in the lungs and kidneys, being inhibited by melatonin administration.

Significance

Thus, we can conclude that doses of 150 and 300 μg/30 g of melatonin for 12 consecutive days have a very effective oncostatic and cytotoxic activity on EAT cells in mice.     

High-dose of vitamin C supplementation reduces amyloid plaque burden and ameliorates pathological changes in the brain of 5XFAD mice

Blood–brain barrier (BBB) breakdown and mitochondrial dysfunction have been implicated in the pathogenesis of Alzheimer''s disease (AD), a neurodegenerative disease characterized by cognitive deficits and neuronal loss. Besides vitamin C being as one of the important antioxidants, recently, it has also been reported as a modulator of BBB integrity and mitochondria morphology. Plasma levels of vitamin C are decreased in AD patients, which can affect disease progression. However, investigation using animal models on the role of vitamin C in the AD pathogenesis has been hampered because rodents produce with no dependence on external supply. Therefore, to identify the pathogenic importance of vitamin C in an AD mouse model, we cross-bred 5 familial Alzheimer''s disease mutation (5XFAD) mice (AD mouse model) with ι-gulono-γ-lactone oxidase (Gulo) knockout (KO) mice, which are unable to synthesize their own vitamin C, and produced Gulo KO mice with 5XFAD mice background (KO-Tg). These mice were maintained on either low (0.66 g/l) or high (3.3 g/l) supplementation of vitamin C. We found that the higher supplementation of vitamin C had reduced amyloid plaque burden in the cortex and hippocampus in KO-Tg mice, resulting in amelioration of BBB disruption and mitochondrial alteration. These results suggest that intake of a larger amount of vitamin C could be protective against AD-like pathologies.     

Antitumor action and immune activation through cooperation of bee venom secretory phospholipase A2 and phosphatidylinositol-(3,4)-bisphosphate

We evaluated tumor cell growth modulation by bee venom secretory phospholipase A2 (bv-sPLA2) and phosphatidylinositol-(3,4)-bisphosphate as well as potential cooperative effects. In addition, the immunomodulatory impact of tumor cell treatment was examined by monitoring changes in phenotype and function of monocyte-derived dendritic cells (moDCs) cocultured with pretreated tumor cells. Bv-sPLA2 or phosphatidylinositol-(3,4)-bisphosphate alone displayed moderate effects on the proliferation of A498 renal cell carcinoma cells, T-47D breast cancer cells, DU145 prostate cancer cells and BEAS-2B transformed lung cells. However, when bv-sPLA2 was coadministered with phosphatidylinositol-(3,4)-bisphosphate a potent inhibition of [³H] thymidine incorporation into all tested cell lines occurred. This inhibition was due to massive cell lysis that reduced the number of cells with proliferative capacity. Importantly, tumor cell lysates generated with bv-sPLA2 plus phosphatidylinositol-(3,4)-bisphosphate induced maturation of human moDCs demonstrated by enhanced expression of CD83 and improved stimulation in allogeneic mixed leukocyte reactions. Our data demonstrate that bv-sPLA2 and phosphatidylinositol-(3,4)-bisphosphate synergistically generate tumor lysates which enhance the maturation of immunostimulatory human monocyte-derived dendritic cells. Such tumor lysates which represent complex mixtures of tumor antigens and simultaneously display potent adjuvant properties meet all requirements of a tumor vaccine.     

Interleukin-18 reduces expression of cardiac tumor necrosis factor-alpha and atrial natriuretic peptide in a murine model of viral myocarditis

Heart failure is generally believed to begin with myocyte damage caused by a variety of insults, including ischemia, toxin or myocardial infection. The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), has been hypothesized to play a pathogenetic role in the transition from compensated to decompensated heart failure. Interleukin-18 (IL-18), a recently cloned cytokine synthesized by Kupffer cells, activates macrophages. We examined the therapeutic effect of IL-18 on the modulation of TNF-alpha gene expression in failing heart in a murine model of heart failure caused by viral myocarditis. The heart weight (HW)/ body weight (BW) ratio in IL-18 treated mice 7 days after viral inoculation was significantly lower (P<0.01) than in the untreated controls. Myocardial necrosis and inflammatory cell infiltration were significantly lower in IL-18 treated mice than untreated mice 5 and 7 days after inoculation. The expression of TNF-alpha mRNA in the myocardium was significantly lower on days 5 and 7 in IL-18 treated mice than in infected untreated mice. We conclude that concurrent systemic administration of IL-18 is beneficial in mice with myocarditis, and may be mediated through reduced expression of TNF-alpha in the heart.     

Polydatin ameliorates chemotherapy-induced cognitive impairment (chemobrain) by inhibiting oxidative stress,inflammatory response,and apoptosis in rats

ABSTRACT

Most breast cancer survivors receiving chemotherapy have severe cognitive impairment, often referred to as “chemobrain.” Polydatin (PLD) is known to have many biological activities. Thus, this study aimed to determine whether symptoms of chemobrain can be prevented or relieved by PLD. The chemobrain models were established by intraperitoneal injection of doxorubicin (DOX, 2 mg/kg) in rats once a week for 4 weeks (DOX group and DOX+PLD group). In the PLD group and DOX+PLD group, PLD (50 mg/kg) was administered orally to rats every day. We found that PLD treatment significantly protected against DOX-induced learning and memory impairment, restored hippocampal histopathological architecture. Furthermore, PLD suppressed DOX-induced oxidative stress through up-regulating Nrf2, inhibited inflammatory response by activating the NF-κB pathway, and reduced hippocampal apoptosis. Therefore, the present study indicated that PLD offered neuroprotection against DOX-induced chemobrain. PLD may assist in preventing chemobrain after chemotherapy in patients with cancers.     

Organoselenium (Sel-Plex diet) decreases amyloid burden and RNA and DNA oxidative damage in APP/PS1 mice

To evaluate potential antioxidant characteristics of organic selenium (Se), double knock-in transgenic mice expressing human mutations in the amyloid precursor protein (APP) and human presenilin-1 (PS1) were provided a Se-deficient diet, a Se-enriched diet (Sel-Plex), or a control diet from 4 to 9 months of age followed by a control diet until 12 months of age. Levels of DNA, RNA, and protein oxidation as well as lipid peroxidation markers were determined in all mice and amyloid β-peptide (Aβ) plaques were quantified. APP/PS1 mice provided Sel-Plex showed significantly (P < 0.05) lower levels of Aβ plaque deposition and significantly decreased levels of DNA and RNA oxidation. Sel-Plex-treated mice showed no significant differences in levels of lipid peroxidation or protein oxidation compared to APP/PS1 mice on a control diet. To determine if diminished oxidative damage was associated with increased antioxidant enzyme activities, brain glutathione peroxidase (GSH-Px), glutathione reductase, and glutathione transferase activities were measured. Sel-Plex-treated mice showed a modest but significant increase in GSH-Px activity compared to mice on a normal diet (P < 0.5). Overall, these data suggest that organic Se can reduce Aβ burden and minimize DNA and RNA oxidation and support a role for it as a potential therapeutic agent in neurologic disorders with increased oxidative stress.     

Antioxidative effects of hesperetin against 7,12-dimethylbenz(a)anthracene-induced oxidative stress in mice

We investigated the effects of the chronic administration of hesperetin on the activation of the antioxidant defence system in mice in which oxidative stress had been induced by 7,12-dimethylbenz(a)anthracene (DMBA). Mice were divided randomly into three treatment groups. Hesperetin was administered orally to two of the three groups at 10 and 50 mg/kg body weight for 5 weeks. Subsequently, each group was subdivided randomly into DMBA-treated and untreated groups. The DMBA-treated groups were intragastrically administered a dose of 34 mg/kg BW in corn oil vehicle twice a week for 2 weeks. The TBARS value showed a tendency to decrease following hesperetin treatment; these decreases were significantly greater in the DMBA-treated than the untreated groups. Hesperetin significantly decreased the carbonyl content at the high dose in both DMBA-treated and untreated mice. Catalase and SOD activity were increased by hesperetin; this increase was more pronounced in DMBA-treated than untreated mice. Catalase, Mn-SOD, and CuZn-SOD expression analyses supported these results. Although the GSH-px and GR activity were little affected, hesperetin treatment significantly increased the GSH/GSSG ratio in the DMBA-treated group in a dose-dependent manner. These results suggest that hesperetin shows antioxidant activity and plays a protective role against DMBA-induced oxidative stress.     

卡介苗溶菌黏膜免疫调理剂对激活荷瘤小鼠免疫功能的研究

观察卡介苗溶菌黏膜免疫调理剂对荷瘤小鼠免疫功能的激活。将SPF小鼠分组后用黑色素瘤B16和肝癌实体瘤H22感染,随后以灌胃途径引入本调理剂,分别发现它能促进荷瘤小鼠血清溶菌酶含量上升和T细胞介导的迟发型变态反应增强。试验结果表明,卡介苗溶菌黏膜免疫调理剂对荷瘤小鼠有升高其血清溶菌酶含量和增强迟发型变态反应的作用。     

Cnida discharge and the mechanism of venom delivery in Anemonia viridis (Cnidaria,Actiniaria)

Cnida discharge in the actinian Anemonia starts with the extrusion of the capsule from the cnidocyte followed by the eversion of the tubule. As the tubule everts, it maintains a tightly closed tip until fully everted. This is considered to be essential for a capsule to discharge as a result of an increase in intracapsular pressure. Venom volumes were measured in 3 types of nematocyst: 408 µm³, 98 µm³, and 9 µm³. Venom flow rates were estimated to range from >43 to 324 µm³ s^–1. It is suggested that the intracapsular pressures required for these flow rates range from 9.7 × 10⁵ to 1.9 x 10⁶ Pa.     

Fumonisin B(1) alters sphingolipid metabolism and tumor necrosis factor alpha expression in heart and lung of mice

Fumonisin B(1) (FB(1)), produced by Fusarium verticillioides, is a common contaminant in foods and feeds. Increase in tissue free sphingoid bases resulting from the inhibition of ceramide synthase is a biomarker of fumonisin exposure. Tumor necrosis factor alpha (TNFalpha) is induced in liver in response to FB(1) treatment. This study determined whether fumonisin B(1) caused increases in free sphingoid bases and altered the expression of TNFalpha in heart and lung, organs that are not targets of FB(1) toxicity, of male and female mice treated with 5-daily subcutaneous injection of 2.25 mg/kg FB(1). A significant increase in free sphingoid bases was observed in both heart and lung of FB(1)-exposed mice. The magnitude of increases in free sphingoid bases in both organs of female mice was much higher than that in males. The expression of TNFalpha was increased by FB(1) treatment in the lung of male mice and in the heart of female mice, whereas the expression of interferon gamma was unaltered. Results suggest that both sphingolipid accumulation and TNFalpha induction are observed in the tissues of mice that are not associated with FB(1) toxicity.     

Probucol modulates iron nitrilotriacetate (Fe-NTA)-dependent renal carcinogenesis and hyperproliferative response: diminution of oxidative stress

Probucol is a clinically used cholesterol-lowering drug, with pronounced antioxidant properties. We have reported previously, that dietary supplementation of probucol enhances NAD(P)H:quinone reductase (Iqbal M, Okada S (2003) Pharmacol Toxicol 93:259–263) and inhibits Fe-NTA induced lipid peroxidation and DNA damage in vitro (Iqbal M, Sharma SD, Oakada (2004) Redox Rep 9:167–172). Further to this, in the present study, we evaluated the modulatory effect of probucol on iron nitrilotriacetae (Fe-NTA) dependent renal carcinogenesis, hyperproliferative response and oxidative stress. In Fe-NTA alone treated group, a 20% renal cell tumor incidence was recorded whereas, in N-diethylnitrosamine (DEN)-initiated and Fe-NTA promoted animals, the percentage tumor incidence was increased to 70% as compared with untreated controls. No tumor incidence was recorded in DEN-initiated, nonpromoted group. Diet supplemented with 1.0% probucol fed prior to, during and after Fe-NTA treatment in DEN-initiated animals afforded >65% protection in renal cell tumor incidence. Probucol fed diet pretreatment also resulted a significant and dose dependent inhibition of Fe-NTA induced renal ornithine decarboxylase (ODC) activity. In oxidative stress studies, Fe-NTA alone treatment enhanced lipid peroxidation, accompanied by a decrease in the level of GSH, activities of antioxidants and phase II metabolizing enzymes in kidney concomitant with histolopathological changes. These changes were significantly and dose-dependently alleviated by probucol fed diet. From this data, it can be concluded that probucol can modulates toxic and tumor promoting effects of Fe-NTA and can serve as a potent chemopreventive agent to suppress oxidant induced tissue injury and carcinogenesis, in addition to being a cholesterol lowering and anti-atherogenic drug.     

(-)Schisandrin B ameliorates paraquat-induced oxidative stress by suppressing glutathione depletion and enhancing glutathione recovery in differentiated PC12 cells

Exposure to paraquat (PQ; N,N'-dimethyl-4-4'-bipyridium), a potent herbicide, can lead to neuronal cell death and increased risk of Parkinson's disease because of oxidative stress. In this study, we investigated the effect of (-)schisandrin B [(-)Sch B, a potent enantiomer of schisandrin B] on PQ-induced cell injury in differentiated pheochromocytoma cells (PC12). PQ treatment caused cell injury in PC12 cells, as indicated by the significant increase in lactate dehydrogenase (LDH) leakage. Pretreatment with (-)Sch B (5 μM) protected against PQ-induced toxicity in PC12 cells, as evidenced by the significant decrease in LDH leakage. (-)Sch B induced the cytochrome P-450-mediated reactive oxygen species generation in differentiated PC12 cells. The cytoprotection afforded by (-)Sch B pretreatment was associated with an increase in cellular reduced glutathione (GSH) level as well as the enhancement of γ-glutamylcysteine ligase (GCL) and glutathione reductase (GR) activity in PQ-challenged cells. Both GCL and GR inhibitors abrogated the cytoprotective effect of (-)Sch B in PQ-challenged cells. The biochemical mechanism underlying the GSH-enhancing effect of (-)Sch B was further investigated in PC12 cells subjected to an acute peroxide challenge. Although the initial GSH depletion induced by peroxide was reduced through GR-catalyzed regeneration of GSH in (-)Sch B-pretreated cells, the later enhanced GSH recovery was mainly mediated by GCL-catalyzed GSH synthesis. The results suggest that (-)Sch B treatment may increase the resistance of dopaminergic cells against PQ-induced oxidative stress through reducing the extent of oxidant-induced GSH depletion and enhancing the subsequent GSH recovery.