Protective effects of antioxidant combination against D‐galactosamine‐induced kidney injury in rats

The protective effects of an antioxidant combination in kidney injury induced by the injection of D‐galactosamine (D‐GaIN) were examined in the present study. Sprague Dawley female rats were used and divided into four groups as follows: (1) animals injected physiological saline solution, intraperitoneally, (2) animals treated with the combination of ascorbic acid (100 mg kg^?1 day^?1), β‐carotene (15 mg kg^?1 day^?1), α‐tocopherol (100 mg kg^?1 day^?1), and sodium selenate (0.2 mg kg^?1 day^?1) for three days orally, (3) rats injected D‐GaIN (500 mg kg^?1) intraperitoneally as a single dose, and (4) animals treated with the antioxidant combination for three days, then injected D‐GaIN. The tissue and blood samples of animals were collected for morphological and biochemical evaluations. Histopathological injury in kidney tissues was observed together with a significant increase in tissue lipid peroxidation (LPO) level, myeloperoxidase (MPO), lactate dehydrogenase, catalase and superoxide dismutase (SOD) activities, and serum creatinine and urea levels, and a significant decrease in glutathione level and glutathione peroxidase activity in D‐GaIN injected rats. However, a decrease in the degenerative changes was detected in the kidney tissue of D‐GaIN + antioxidant group, and biochemical results showed reversed effects. In conclusion, it seems reasonable to conclude that the treatment of the antioxidant combination has a protective effect on D‐GaIN‐induced kidney injury of rats. Copyright © 2010 John Wiley & Sons, Ltd.     

Pyrroloquinoline quinone ameliorates l‐thyroxine‐induced hyperthyroidism and associated problems in rats

Pyrroloquinoline quinone (PQQ) is believed to be a strong antioxidant. In this study, we have evaluated its hitherto unknown role in l ‐thyroxin (L‐T₄)‐induced hyperthyroidism considering laboratory rat as a model. Alterations in the serum concentration of thyroxin (T₄) and triiodothyronine (T₃); lipid peroxidation (LPO) of liver, kidney, heart, muscles and brain; in the endogenous antioxidants such as superoxide dismutase, catalase and glutathione and in serum total cholesterol, high‐density lipoprotien, triglycerides, serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT) and urea were evaluated. Administration of l ‐T₄ (500‐µg kg^?1 body weight) enhanced not only the serum T₃ and T₄ levels but also the tissue LPO, serum SGOT, SGPT and urea with a parallel decrease in the levels of antioxidants and serum lipids. However, on simultaneous administration of PQQ (5 mg kg^?1 for 6 days), all these adverse effects were ameliorated, indicating the potential of PQQ in the amelioration of hyperthyroidism and associated problems. Possibly, the curative effects were mediated through inhibition of oxidative stress. We suggest that PQQ may be considered for therapeutic use for hyperthyroidism after dose standardization. Copyright © 2014 John Wiley & Sons, Ltd.     

Methylmercury toxicity: amelioration by selenium and water‐soluble chelators as N‐acetyl cysteine and dithiothreitol

The protective potential of chelators, i.e. N‐acetyl cysteine (0.6 mg /kg, intraperitoneally) and dithiothreitol (15.4 mg kg^?1, intraperitoneally) with selenium (0.5 mg kg^?1, pre‐oral) were evaluated individually and in combination against methylmercury‐induced biochemical alterations and oxidative stress consequences. Forty‐two male Sprague–Dawley rats were exposed with methylmercury (1.5 mg kg^?1, pre‐oral) daily for 21 days followed by different treatments for five consecutive days. Administration of methylmercury caused significant enhancement in the release of transaminases, alkaline phosphatases and lactate dehydrogenases in serum. A significant increased was observed in lipid peroxidation level with a concomitant decreased in glutathione content after methylmercury exposure in liver, kidney and brain. Hepatic microsomal drug metabolizing enzymes (aniline hydroxylase and amidopyrine N‐demethylase) of cytochrome p4502E₁ showed sharp depletion after methylmercury exposure. Alterations in histological changes in liver, kidney and brain were also noted in methylmercury administered group. All treated groups showed recovery pattern, but the combined treatments with N‐acetyl cysteine and dithiothreitol in combination with selenium were more effective than that with either alone treatments in recovering blood biochemical changes after methylmercury toxicity. In conclusion, the results demonstrated that combination therapy may recover all blood biochemical alterations and offer maximum protection against methylmercury‐induced toxicity. Copyright © 2014 John Wiley & Sons, Ltd.     

Wnt/β‐catenin/RAS signaling mediates age‐related renal fibrosis and is associated with mitochondrial dysfunction

Renal fibrosis is the common pathological feature in a variety of chronic kidney diseases. Aging is highly associated with the progression of renal fibrosis. Among several determinants, mitochondrial dysfunction plays an important role in aging. However, the underlying mechanisms of mitochondrial dysfunction in age‐related renal fibrosis are not elucidated. Herein, we found that Wnt/β‐catenin signaling and renin–angiotensin system (RAS) activity were upregulated in aging kidneys. Concomitantly, mitochondrial mass and functions were impaired with aging. Ectopic expression of Klotho, an antagonist of endogenous Wnt/β‐catenin activity, abolished renal fibrosis in d ‐galactose (d ‐gal)‐induced accelerated aging mouse model and significantly protected renal mitochondrial functions by preserving mass and diminishing the production of reactive oxygen species. In an established aging mouse model, dickkopf 1, a more specific Wnt inhibitor, and the mitochondria‐targeted antioxidant mitoquinone restored mitochondrial mass and attenuated tubular senescence and renal fibrosis. In a human proximal tubular cell line (HKC‐8), ectopic expression of Wnt1 decreased biogenesis and induced dysfunction of mitochondria, and triggered cellular senescence. Moreover, d ‐gal triggered the transduction of Wnt/β‐catenin signaling, which further activated angiotensin type 1 receptor (AT1), and then decreased the mitochondrial mass and increased cellular senescence in HKC‐8 cells and primary cultured renal tubular cells. These effects were inhibited by AT1 blocker of losartan. These results suggest inhibition of Wnt/β‐catenin signaling and the RAS could slow the onset of age‐related mitochondrial dysfunction and renal fibrosis. Taken together, our results indicate that Wnt/β‐catenin/RAS signaling mediates age‐related renal fibrosis and is associated with mitochondrial dysfunction.     

Native LDL‐induced oxidative stress in human proximal tubular cells: multiple players involved

Dyslipidemia is a well‐established condition proved to accelerate the progression of chronic kidney disease leading to tubulo‐interstitial injury. However, the molecular aspects of the dyslipidemia‐induced renal damage have not been fully clarified and in particular the role played by low‐density lipoproteins (LDLs). This study aimed to examine the effects of native non‐oxidized LDL on cellular oxidative metabolism in cultured human proximal tubular cells. By means of confocal microscopy imaging combined to respirometric and enzymatic assays it is shown that purified native LDL caused a marked increase of cellular reactive oxygen species (ROS) production, which was mediated by activation of NADPH oxidase(s) and by mitochondrial dysfunction by means of a ROS‐induced ROS release mechanism. The LDL‐dependent mitochondrial alterations comprised inhibition of the respiratory chain activity, enhanced ROS production, uncoupling of the oxidative phosphorylation efficiency, collapse of the mtΔΨ, increased Ca²⁺ uptake and loss of cytochrome c. All the above LDL‐induced effects were completely abrogated by chelating extracellular Ca²⁺ as well as by inhibition of the Ca²⁺‐activated cytoplas‐mic phospholipase A2, NADPH oxidase and mitochondrial permeability transition. We propose a mechanicistic model whereby the LDL‐induced intracellular redox unbalance is triggered by a Ca²⁺ inward flux‐dependent commencement of cPLA2 followed by activation of a lipid‐ and ROS‐based cross‐talking signalling pathway. This involves first oxidants production via the plasmamembrane NADPH oxidase and then propagates downstream to mitochondria eliciting redox‐ and Ca²⁺‐dependent dysfunctions leading to cell‐harming conditions. These findings may help to clarify the mechanism of dyslipidemia‐induced renal damage and suggest new potential targets for specific therapeutic strategies to prevent oxidative stress implicated in kidney diseases.     

Mitochondrial peroxiredoxin‐5 as potential modulator of mitochondria‐ER crosstalk in MPP+‐induced cell death

Peroxiredoxin‐5 (PRDX5) is an antioxidant enzyme which differs from the other peroxiredoxins with regards to its enzymatic mechanism, its high affinity for organic peroxides and peroxynitrite and its wide subcellular distribution. In particular, the mitochondrial isoform of PRDX5 confers a remarkable cytoprotection toward oxidative stress to mammalian cells. Mitochondrial dysfunction and disruption of Ca²⁺ homeostasis are implicated in neurodegeneration. Growing evidence supports that endoplasmic reticulum (ER) could operate in tandem with mitochondria to regulate intracellular Ca²⁺ fluxes in neurodegenerative processes. Here, we overexpressed mitochondrial PRDX5 in SH‐SY5Y cells to dissect the role of this enzyme in 1‐methyl‐4‐phenylpyridinium (MPP)⁺‐induced cell death. Our data show that mitochondria‐dependent apoptosis triggered by MPP⁺, assessed by the measurement of caspase‐9 activation and mitochondrial DNA damage, is prevented by mitochondrial PRDX5 overexpression. Moreover, PRDX5 overexpression blocks the increase in intracellular Ca²⁺, Ca²⁺‐dependent activation of calpains and Bax cleavage. Finally, using Ca²⁺ channel inhibitors (Nimodipine, Dantrolene and 2‐APB), we show that Ca²⁺ release arises essentially from ER stores through 1,4,5‐inositol‐trisphosphate receptors (IP₃R). Altogether, our results suggest that the MPP⁺ mitochondrial pathway of apoptosis is regulated by mitochondrial PRDX5 in a process that could involve redox modulation of Ca²⁺ transporters via a crosstalk between mitochondria and ER.     

Protective effect of binaphthyl diselenide,a synthetic organoselenium compound,on 2‐nitropropane‐induced hepatotoxicity in rats

Organoselenides have been documented as promising pharmacological agents against a number of diseases associated with oxidative stress. Here we have investigated, for the first time, the potential antioxidant activity of binaphthyl diselenide ((NapSe)₂; 50 mg kg^?1, p.o.) against the 2‐nitropropane (2‐NP)‐induced hepatoxicity in rats, using different end points of toxicity (liver histopathology, plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatinine). In addition, in view of the association of oxidative stress with 2‐NP exposure, hepatic lipid peroxidation, ascorbic acid levels, δ‐aminolevulinate dehydratase (δ‐ALA‐D) and catalase (CAT) activities were evaluated. 2‐NP caused an increase of AST, ALT and hepatic lipid peroxidation. 2‐NP also caused hepatic histopathological alterations and δ‐ALA‐D inhibition. (NapSe)₂ (50 mg kg^?1) prevented 2‐NP‐induced changes in plasmatic ALT and AST activities and also prevented changes in hepatic histology, δ‐ALA‐D and lipid peroxidation. Results presented here indicate that the protective mechanism of (NapSe)₂ against 2‐NP hepatotoxicity is possibly linked to its antioxidant activity. Copyright © 2010 John Wiley & Sons, Ltd.     

Response of mitochondrial antioxidant system and respiratory pathways to reactive nitrogen species in pea leaves

Nitric oxide (NO) has emerged as an important signaling molecule in plants, but little is known about the effects of reactive nitrogen species in plant mitochondria. In this study, the effects of DETA‐NONOate, a pure NO slow generator, and of SIN‐1 (3‐morpholinosydnonimine), a peroxynitrite producer, on the activities of respiratory pathways, enzymatic and non‐enzymatic antioxidants have been investigated in isolated mitochondria from pea leaves. No significant changes in lipid peroxidation, protein oxidation or in ascorbate and glutathione redox state were observed after DETA‐NONOate treatments whereas cytochrome pathway (CP) respiration was reversibly inhibited and alternative pathway (AP) respiration showed little inhibition. On the other hand, NO did not affect neither activities of Mn superoxide dismutase (Mn‐SOD) nor enzymes involved in the ascorbate and glutathione regeneration in mitochondria except for ascorbate peroxidase (APX), which was reversely inhibited depending on ascorbate concentration. Finally, SIN‐1 treatment of mitochondria produced a decrease in CP respiration, an increase in protein oxidation and strongly inhibited APX activity (90%), with glutathione reductase and dehydroascorbate reductase (DHAR) being moderately inhibited (30 and 20%, respectively). This treatment did not affect monodehydroascorbate reductase (MDHAR) and Mn‐SOD activities. Results showed that mitochondrial nitrosative stress was not necessarily accompanied by oxidative stress. We suggest that NO‐resistant AP and mitochondrial APX may be important components of the H₂O₂‐signaling pathways under nitrosative stress induced by NO in this organelle. Also, MDHAR and DHAR, via ascorbate regeneration, could constitute an essential antioxidant defense together with Mn‐SOD, against NO and ONOO^? stress in plant mitochondria.     

Treatment with the mitochondrial‐targeted antioxidant peptide SS‐31 rescues neurovascular coupling responses and cerebrovascular endothelial function and improves cognition in aged mice

Moment‐to‐moment adjustment of cerebral blood flow (CBF) via neurovascular coupling has an essential role in maintenance of healthy cognitive function. In advanced age, increased oxidative stress and cerebromicrovascular endothelial dysfunction impair neurovascular coupling, likely contributing to age‐related decline of higher cortical functions. There is increasing evidence showing that mitochondrial oxidative stress plays a critical role in a range of age‐related cellular impairments, but its role in neurovascular uncoupling remains unexplored. This study was designed to test the hypothesis that attenuation of mitochondrial oxidative stress may exert beneficial effects on neurovascular coupling responses in aging. To test this hypothesis, 24‐month‐old C57BL/6 mice were treated with a cell‐permeable, mitochondria‐targeted antioxidant peptide (SS‐31; 10 mg kg^?1 day^?1, i.p.) or vehicle for 2 weeks. Neurovascular coupling was assessed by measuring CBF responses (laser speckle contrast imaging) evoked by contralateral whisker stimulation. We found that neurovascular coupling responses were significantly impaired in aged mice. Treatment with SS–31 significantly improved neurovascular coupling responses by increasing NO‐mediated cerebromicrovascular dilation, which was associated with significantly improved spatial working memory, motor skill learning, and gait coordination. These findings are paralleled by the protective effects of SS–31 on mitochondrial production of reactive oxygen species and mitochondrial respiration in cultured cerebromicrovascular endothelial cells derived from aged animals. Thus, mitochondrial oxidative stress contributes to age‐related cerebromicrovascular dysfunction, exacerbating cognitive decline. We propose that mitochondria‐targeted antioxidants may be considered for pharmacological microvascular protection for the prevention/treatment of age‐related vascular cognitive impairment (VCI).     

Influence of kolaviron and vitamin E on ethylene glycol monoethyl ether‐induced haematotoxicity and renal apoptosis in rats

The present study investigated the protective effects of kolaviron, a biflavonoid from the seed of Garcinia kola, and vitamin E on ethylene glycol monoethyl ether (EGEE)‐induced haematotoxicity and renal apoptosis in male rats. EGEE was administered at a dose of 200 mg kg^?1 alone or simultaneously administered with kolaviron (100 and 200 mg kg^?1) and vitamin E (50 mg kg^?1) for 14 days. Results of haematological examination showed that white blood cells, platelets, neutrophils and mean corpuscular haemoglobin concentration were significantly lower, whereas lymphocytes were increased in EGEE‐exposed rats compared with those in the control. Administration of EGEE caused a significant decrease in the superoxide dismutase and catalase activities as well as in the glutathione level but significantly increased glutathione Stransferase activity and levels of hydrogen peroxide and lipid peroxidation in kidneys of rats compared with those in the control. Also, EGEE‐treated rats showed significant elevation in the serum urea and creatinine with marked increase in the frequency of terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling assay‐positive apoptotic cells in the tubular epithelial cells in comparison with the control. Co‐administration with kolaviron or vitamin E exhibited chemoprotective effects against EGEE‐mediated haematotoxicity, augmented renal antioxidant status and prevented the induction of renal apoptosis. Copyright © 2013 John Wiley & Sons, Ltd.     

The effects of vitamins and selenium mixture against brain tissue induced by d‐galactosamine

Brain damage is a major complication of fulminant hepatic failure. d ‐Galactosamine (d ‐GalN)‐induced liver toxicity causes damage to brain. The effects of vitamins and selenium mixture against d ‐GalN stimulated brain injury were investigated in this study. Sprague‐Dawley female rats aged 2.0‐2.5 months were used for the study. The rats were divided into four categories. A 0.9% NaCl solution was intraperitoneally given to the experimental rats in the first group. Using gavage technique, the second group of animals were subjected to a formulation consisting of 100 mg·kg^?1·day^?1 vitamin C, 15 mg·kg^?1·day^?1 of β‐carotene, 100 mg·kg^?1·day^?1 of α‐tocopherol in addition to 0.2 mg·kg^?1·day^?1 of sodium selenate for 3 days. The third group was given a single dose of d ‐GalN hydrochloride at the concentration of 500 mg·kg^?1 through a saline injection. The final group was given similar concentrations of both the antioxidant combination and d ‐GalN. Tissue samples were collected under ether anesthesia. The rats treated with d ‐GalN showed brain damage; increased myeloperoxidase, catalase, glutathione peroxidase, glutathione‐S‐transferase, lactate dehydrogenase, and superoxide dismutase activities; and decreased glutathione levels. Treatment with vitamins and selenium combination resulted in alleviation of these alterations in the rats. These findings suggest that administration of the vitamins and selenium combination suppresses oxidative stress and protects brain cells from injury induced by d ‐GalN.     

Galangin,a natural flavonoid reduces mitochondrial oxidative damage in streptozotocin-induced diabetic rats

Objective: We designed this study to observe the effect of galangin on damaged mitochondria in the liver of diabetic rats.

Methods: Male albino Wistar rats were made diabetic by injecting streptozotocin (STZ) intraperitoneally (40?mg?kg^?1 body weight (BW)). Galangin (8?mg?kg^?1 BW) or glibenclamide (600?µg?kg^?1 BW) was given orally daily once for 45 days to both healthy and diabetic rats.

Results: Diabetic rats showed significant (P?P?P?P?P?Conclusion: From the results, we conclude that galangin could maintain liver mitochondrial function in diabetic rats.     

Long‐term intake of phenolic compounds attenuates age‐related cardiac remodeling

With the onset of advanced age, cardiac‐associated pathologies have increased in prevalence. The hallmarks of cardiac aging include cardiomyocyte senescence, fibroblast proliferation, inflammation, and hypertrophy. The imbalance between levels of reactive oxygen species (ROS) and antioxidant enzymes is greatly enhanced in aging cells, promoting cardiac remodeling. In this work, we studied the long‐term impact of phenolic compounds (PC) on age‐associated cardiac remodeling. Three‐month‐old Wistar rats were treated for 14 months till middle‐age with either 2.5, 5, 10, or 20 mg kg^?1 day^?1 of PC. PC treatment showed a dose‐dependent preservation of cardiac ejection fraction and fractional shortening as well as decreased hypertrophy reflected by left ventricular chamber diameter and posterior wall thickness as compared to untreated middle‐aged control animals. Analyses of proteins from cardiac tissue showed that PC attenuated several hypertrophic pathways including calcineurin/nuclear factor of activated T cells (NFATc3), calcium/calmodulin‐dependent kinase II (CAMKII), extracellular regulated kinase 1/2 (ERK1/2), and glycogen synthase kinase 3ß (GSK 3ß). PC‐treated groups exhibited reduced plasma inflammatory and fibrotic markers and revealed as well ameliorated extracellular matrix remodeling and interstitial inflammation by a downregulated p38 pathway. Myocardia from PC‐treated middle‐aged rats presented less fibrosis with suppression of profibrotic transforming growth factor‐ß1 (TGF‐ß1) Smad pathway. Additionally, reduction of apoptosis and oxidative damage in the PC‐treated groups was reflected by elevated antioxidant enzymes and reduced RNA/DNA damage markers. Our findings pinpoint that a daily consumption of phenolic compounds could preserve the heart from the detrimental effects of aging storm.     

Modulator Effects of Meloxicam against Doxorubicin‐Induced Nephrotoxicity in Mice

Doxorubicin‐induced renal toxicity overshadows its anticancer effectiveness. This study is aimed at assessing the possible modulator effects of meloxicam, a cyclooxigenase‐2 inhibitor, on doxorubicin‐induced nephrotoxicity in mice and exploring some of the modulator mechanisms. Forty male mice were divided for treatment, for 2 weeks, with saline, meloxicam (daily), doxorubicin (twice/week), or both meloxicam and doxorubicin. Doxorubicin induced a significant increase in relative kidney weight to body weight, kidney lipid perooxidation, plasma levels of interleukin‐6 and tumor necrosis factor‐α, kidney caspase‐3 activity, and kidney prostaglandin E2 (PGE2) content. Doxorubicin disturbed kidney histology, abrogated renal function tests (serum creatinine, uric acid, and blood urea nitrogen), induced a significant decrease in antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, and catalase) and reduced glutathione (GSH) content. The administration of meloxicam with doxorubicin mitigated all doxorubicin‐disturbed parameters. Meloxicam ameliorated doxorubicin‐induced renal injury via inhibition of inflammatory PGE2, inflammatory cytokines, caspase‐3 activity, antioxidant effect, and free radical scavenging activity.     

10H‐3,6‐Diazaphenothiazines triggered the mitochondrial‐dependent and cell death receptor‐dependent apoptosis pathways and further increased the chemosensitivity of MCF‐7 breast cancer cells via inhibition of AKT1 pathways

Breast cancer is one of the leading causes of death in cancer categories, followed by lung, colorectal, and ovarian among the female gender across the world. 10H‐3,6‐diazaphenothiazine (PTZ) is a thiazine derivative compound that exhibits many pharmacological activities. Herein, we proceed to investigate the pharmacological activities of PTZ toward breast cancer MCF‐7 cells as a representative in vitro breast cancer cell model. The PTZ exhibited a proliferation inhibition (IC₅₀ = 0.895 µM) toward MCF‐7 cells. Further, cell cycle analysis illustrated that the S‐phase checkpoint was activated to achieve proliferation inhibition. In vitro cytotoxicity test on three normal cell lines (HEK293 normal kidney cells, MCF‐10A normal breast cells, and H9C2 normal heart cells) demonstrated that PTZ was more potent toward cancer cells. Increase in the levels of reactive oxygen species results in polarization of mitochondrial membrane potential (ΔΨm), together with suppression of mitochondrial thioredoxin reductase enzymatic activity suggested that PTZ induced oxidative damages toward mitochondria and contributed to improved drug efficacy toward treatment. The RT² PCR Profiler Array (human apoptosis pathways) proved that PTZ induced cell death via mitochondria‐dependent and cell death receptor‐dependent pathways, through a series of modulation of caspases, and the respective morphology of apoptosis was observed. Mechanistic studies of apoptosis suggested that PTZ inhibited AKT1 pathways resulting in enhanced drug efficacy despite it preventing invasion of cancer cells. These results showed the effectiveness of PTZ in initiation of apoptosis, programmed cell death, toward highly chemoresistant MCF‐7 cells, thus suggesting its potential as a chemotherapeutic drug.     

Vitamin E and Hippophea rhamnoides L. extract reduce nicotine‐induced oxidative stress in rat heart

The effects of vitamin E and Hippophea rhamnoides L. extract (HRe‐1) on nicotine‐induced oxidative stress in rat heart were investigated. There were eight rats per group and supplementation period was 3 weeks. The groups were: nicotine [0.5 mg kg^?1day^?1, intraperitoneal (i.p.)]; nicotine plus vitamin E [75 mg kg^?1day^?1, intragastric (i.g.)]; nicotine plus HRe‐1 (250 mg kg^?1day^?1, i.g.); and the control group (receiving only vehicles). Nicotine increased the malondialdehyde level, which was prevented by both vitamin E and HRe‐1. Glutathione peroxidase (GPx) activity in nicotine plus vitamin E supplemented group was higher than the others. Glutathione S‐transferase (GST) activity in nicotine plus HRe‐1 supplemented group was increased compared with the control group. Catalase activity was higher in nicotine group compared with others. GPx activity in nicotine plus vitamin E supplemented group was elevated compared with the others. Total and non‐enzymatic superoxide scavenger activities in nicotine plus vitamin E supplemented group were lower than nicotine plus HRe‐1 supplemented group. Superoxide dismutase (SOD) activity was higher in nicotine plus HRe‐1 supplemented group compared with others. Glutathione reductase activity and nitric oxide level were not affected. Increased SOD and GST activities might have taken part in the prevention of nicotine‐induced oxidative stress in HRe‐1 supplemented group in rat heart. Flavonols such as quercetin, and isorahmnetin, tocopherols such as α‐tocopherol and β‐tocopherol and carotenoids such as α‐carotene and β‐carotene, reported to be present in H. rhamnoides L. extracts may be responsible for the antioxidant effects of this plant extract. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of desipramine on the antioxidant status in rat tissues at carrageenan‐induced paw inflammation

The pathogenesis of many diseases and different pathological conditions, including inflammation, is associated with excess production of reactive oxygen species (ROS). The present study aimed to investigate the effects of the antidepressant desipramine (DES) on carrageenan (CG)‐induced inflammation, as well as on the endogenous levels of cell enzyme and non‐enzyme antioxidants in rat liver and spleen, 4 and 24 h after CG injection. The intra‐plantar CG injection into the right hind paw resulted in a time‐dependent increase in the paw volume; the maximum of CG‐induced edema peak was in 2–4 h. A single DES dose of 20 mg·kg^?1, administered 30 min before CG, had no effect on paw edema, whereas the higher drug dose used (50 mg·kg^?1) suppressed the edematous response to CG. The latter drug dose protected CG‐induced decrease of glutathione (non‐enzyme antioxidant) in the liver; it did not affect CG‐unchanged activities of superoxide dismutase, glutathione peroxidase (enzyme antioxidants) and glucose‐6‐phosphate dehydrogenase (enzyme, important for the activity of glutathione‐conjugated antioxidant enzymes) in both liver and spleen. The drug showed an efficient antioxidant capacity in ROS‐generating chemical systems; it was higher than that of fluoxetine (another type of antidepressant). The present results suggest that the good antioxidant activity of DES might contribute to its beneficial effects in liver injuries. Copyright © 2011 John Wiley & Sons, Ltd.     

L‐NAME co‐treatment prevent oxidative damage in the lung of adult Wistar rats treated with vitamin A supplementation

Based on the fact that vitamin A in clinical doses is a potent pro‐oxidant agent to the lungs, we investigated here the role of nitric oxide (NO^?) in the disturbances affecting the lung redox environment in vitamin A‐treated rats (retinol palmitate, doses of 1000–9000 IU·kg^?1·day^?1) for 28 days. Lung mitochondrial function and redox parameters, such as lipid peroxidation, protein carbonylation and the level of 3‐nytrotyrosine, were quantified. We observed, for the first time, that vitamin A supplementation increases the levels of 3‐nytrotyrosine in rat lung mitochondria. To determine whether nitric oxide (NO ?) or its derivatives such as peroxynitrite (ONOO‐) was involved in this damage, animals were co‐treated with the nitric oxide synthase inhibitor L‐NAME (30 mg·kg^?1, four times a week), and we analysed if this treatment prevented (or minimized) the biochemical disturbances resulting from vitamin A supplementation. We observed that L‐NAME inhibited some effects caused by vitamin A supplementation. Nonetheless, L‐NAME was not able to reverse completely the negative effects triggered by vitamin A supplementation, indicating that other factors rather than only NO? or ONOO‐ exert a prominent role in mediating the redox effects in the lung of rats that received vitamin A supplementation. Copyright © 2011 John Wiley & Sons, Ltd.     

Montelukast abrogates prednisolone‐induced hepatic injury in rats: Modulation of mitochondrial dysfunction,oxidative/nitrosative stress,and apoptosis

The aim of this study was to investigate the protective effect of montelukast (MTK) against prednisolone‐induced hepatic injury in rats. Twenty‐eight male albino rats were categorized into four equal groups. Group I served as the control group; group II: rats orally received prednisolone (5 mg·kg^?1·d^?1) for 30 days; groups III and IV: rats orally received MTK at 10 and 20 mg·kg^?1·d^?1, respectively, simultaneously with prednisolone for 30 days. Serum liver enzymes, hepatic mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic markers were evaluated, and the results were confirmed by histopathological examination. MTK showed significant hepatic protection evidenced by alleviated histological lesion and improvement of mitochondrial function, oxidative/nitrosative stress, and inflammatory and apoptotic changes induced by prednisolone, with more profound protection in higher MTK dose (20 mg·kg^?1). In view of these findings, we can conclude that MTK may have hepatoprotective potential, beyond its therapeutic value for asthmatic patients during their course of corticosteroid therapy.     

Mechanisms of Phenytoin‐Induced Toxicity in Freshly Isolated Rat Hepatocytes and the Protective Effects of Taurine and/or Melatonin

Phenytoin is a widely used antiepileptic drug. However, hepatotoxicity is one of its adverse effects reported in some patients. The mechanism(s) by which phenytoin causes hepatotoxicity is not clear yet. This study was designed to evaluate the cytotoxic mechanism(s) of phenytoin toward rat hepatocytes (whose cytochrome P450 enzymes had been induced by Phenobarbital). Furthermore, the effect of taurine and/or melatonin on this toxicity was investigated. Cell death, reactive oxygen species (ROS) formation, lipid peroxidation (LPO), and mitochondrial depolarization were monitored as toxicity markers. Results showed that phenytoin caused an elevation in ROS formation, depletion of intracellular reduced glutathione, increase in cellular oxidized glutathione, enhancement of LPO, and mitochondrial damage. Taurine (1 mM) and/or melatonin (1 mM) administration decreased the intensity of cellular injury caused by phenytoin. This study suggests the protective role of taurine and/or melatonin against phenytoin‐induced cellular damage probably through their reactive radical scavenging properties and their effects on mitochondria.