Protective effect of cysteinyl leukotriene receptor antagonist montelukast in bleomycin-induced pulmonary fibrosis.

BACKGROUND: This study aims to investigate the early- and late-term effects of pharmacological inhibition of cysteinyl leukotriene activity by using montelukast in bleomycin-induced inflammatory and oxidative lung injury in an animal model. METHODS: The study included 48 male Wistar albino rats (weighing 250 g to 300 g). Rats were administered intratracheal bleomycin or saline and assigned into groups to receive montelukast or saline. Bronchoalveolar lavage fluid and lung tissue samples were collected four and 15 days after bleomycin administration. RESULTS: Bleomycin resulted in significant increases in tumor necrosis factor-alpha levels (4.0±1.4 pg/mL in controls vs. 44.1±14.5 pg/mL in early-term vs. 30.3±5.7 pg/mL in late-term, p<0.001 and p<0.001, respectively), transforming growth factor beta 1 levels (28.6±6.6 pg/mL vs. 82.3±14.1 pg/mL in early-term vs. 60.1±2.9 pg/mL in late-term, p<0.001 and p<0.001, respectively), and fibrosis score (1.85±0.89 in early-term vs. 5.60±1.14 in late-term, p<0.001 and p<0.01, respectively). In bleomycin exposed rats, collagen content increased only in the late-term (15.3±3.0 ?g/mg in controls vs. 29.6±9.1 ?g/mg in late-term, p<0.001). Montelukast treatment reversed all these biochemical indices as well as histopathological alterations induced by bleomycin. CONCLUSION: Montelukast attenuates bleomycin-induced inflammatory and oxidative lung injury and prevents lung collagen deposition and fibrotic response. Thus, cysteinyl leukotriene receptor antagonists might be regarded as new therapeutic agents for idiopathic pulmonary fibrosis.

PHARMACODYNAMICAL EVALUATION OF MATRIX TYPE TRANSDERMAL THERAPEUTIC SYSTEMS CONTAINING CAPTOPRIL.

The objective of this study was to evaluate pharmacodynamical properties of transdermal therapeutic systems (TTS) containing captopril together with synthetic and pH independent polymers, Eudragit RL 100 and RS 100. Optimum formulation was chosen according to the results of our previous study regarding in vitro dissolution and ex vivo diffusion rate studies through excised human skin by using Franz Diffusion Cell. Control group, hypertension group (HT) and TTS containing captopril hypertension group (HT-CAP) were assessed for the pharmacodynamic activity of the study. Pharmacodynamic activity of transdermal patches containing captopril was evaluated in rats by the measurement of systolic blood pressure for 24 h with the use of the tail cuff method. Blood pressure, heart rate, body and heart weight, heart and body weight ratio were determined. Lactate dehydrogenase (LDH), creatinine phosphokinase (CPK), glutathione (GSH), malondialdehyde (MDA), myeloperoxidase (MPO) and Na+, K(+)-ATPase were measured in the serum of rats. Histopathological evaluation of the heart tissue was conducted in order to determine any tissue damage. Blood pressure values of the TTS containing captopril hypertension group were decreased significantly and became almost similar with the blood pressure values of the control group. These results indicated that matrix type transdermal patches prepared with Eudragit RL 100 and RS 100 polymers containing captopril can be considered as transdermal therapeutic systems for chronical treatment of hypertension and congestive heart failure. However, further in vivo pharmacokinetic studies should be performed in order to determine the blood level of the drug.

Effect of hyperbaric oxygen treatment in a rat model of abdominal aortic aneurysm.

Matrix metalloproteinase (MMP) plays a pivotal role in the pathophysiology of abdominal aortic aneurysms (AAA). Experimental studies have demonstrated that hyperbaric oxygen (HBO2) therapy decreases MMP levels in different tissues. However, the effect of HBO2 therapy on AAA has yet to be investigated. This study aimed to examine the effects of HBO2 on MMPs in an experimental AAA model. The model was implemented with CaCl2 in 12-week-old male Wistar albino rats. The rats were randomized into four groups: Group I: received NaCl (n = 6) (Sham group); Group II: received NaCl and were treated with HBO2 (n = 6); Group III: received CaCl2 (n = 6); and Group IV: received CaCl2 and were treated with HBO2 (n = 6). HBO2 therapy was applied for five of seven days over a period of six weeks. Although in the CaCl2 groups, aortic diameters were significantly higher than the NaCl groups (p < 0.05), there was no difference between pre- and post-HBO2 in the CaCl2 groups (p > 0.05). In the CaCl2 group, the MMP-2 and MMP-9 levels were significantly higher than those in the NaCl group (p < 0.05). HBO2 therapy had no statistically significant effect on the MMP-2 and MMP-9 levels in Groups III and IV. However, it was observed that both levels clearly decreased in Group IV. In conclusion, the study suggested that HBO2 may have favorable effects on MMP levels.

Resveratrol improves cardiovascular function and reduces oxidative organ damage in the renal, cardiovascular and cerebral tissues of two-kidney, one-clip hypertensive rats.

OBJECTIVES: The putative protective effects of resveratrol against oxidative injury in the heart, kidney and brain tissues of rats induced with the two-kidney, one-clip (2K1C) hypertension model were investigated. METHODS: Wistar albino rats were divided into sham-operated (n = 8) or 2K1C groups, in which rats received either resveratrol (10 mg/kg per day, i.p., n = 8), or saline (n = 8) starting at Week 3 after the surgery and continuing for the following 6 weeks. Indirect blood pressure recordings and echocardiographic images were made to evaluate cardiac function. At the end of Week 9 the animals were decapitated and plasma, heart, kidney and brain were taken for biochemical assays, while aortic rings were prepared for vascular reactivity studies. KEY FINDINGS: 2K1C hypertension resulted in increased blood pressure, aortic hypercontractility and reduced left ventricular function, leading to increased lipid peroxidation and myeloperoxidase activity, concomitant with significant reductions in tissue glutathione, superoxide dismutase, Na+/K+-ATPase and catalase activities in the cardiac, renal and brain tissues, indicating the presence of oxidative tissue damage in peripheral target organs. Elevated plasma levels of lactate dehydrogenase, creatine kinase, as well as reduced plasma levels of antioxidant capacity and nitric oxide further verified the severity of oxidative injury. A 6-week treatment with resveratrol reversed all the measured parameters, ameliorated hypertension-induced oxidative injury in the target organs and improved cardiovascular function. CONCLUSIONS: Resveratrol improved cardiovascular function through the augmentation of endogenous antioxidants and the inhibition of lipid peroxidation by maintaining a balance in oxidant/antioxidant status, which also ameliorated hypertension-induced oxidative injury in the cardiac, renal and cerebral tissues.

Resveratrol protects against methotrexate-induced hepatic injury in rats.

PURPOSE: The aim of this study to investigate the possible protective effect of resveratrol on some liver and serum/plasma parameters in methotrexate induced toxicity in rats. Methotrexate is used widely to treat various neoplastic diseases such as acute lymphoblastic leukemia, lymphoma, solid cancers, and autoimmune diseases. We hypothesized that resveratrol has a potential to decrease the oxidant damage in MTX-induced hepatic injury. METHODS: Following a single dose of methotrexate (20 mg/kg, i.p.), either saline or resveratrol (10 mg/kg, orally) was administered for 5 days. After decapitation of the rats, trunk blood was obtained and the liver was removed to measure malondialdehyde and glutathione levels, myeloperoxidase and thromboplastic activities and collagen content. Aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase activity were measured in the serum samples, while TNF-alpha and total antioxidant capacity were assayed in plasma samples. RESULTS: Our results showed that MTX administration increased the hepatic malondialdehyde levels, myeloperoxidase and thromboplastic activities and collagen contents and decreased glutathione, while these alterations were reversed in resveratrol-treated group. Elevated aspartate aminotransferase and alanine aminotransferase activities and TNF-alpha level observed following MTX treatment was depressed with resveratrol. CONCLUSIONS: The present study showed that resveratrol protects against methotrexate-induced hepatic injury and may be of therapeutic potential in alleviating the systemic side effects of chemotherapeutics.

Protective potential of montelukast against hepatic ischemia/reperfusion injury in rats.

Ischemia and reperfusion (I/R) injury is characterized by significant oxidative stress, characteristic changes in the antioxidant system and organ injury leading to significant morbidity and mortality. This study was designed to assess the possible protective effect of montelukast, a selective antagonist of cysteinyl leukotriene receptor 1 (CysLT1), on hepatic I/R injury in rats. Wistar albino rats through clamping hepatic artery, portal vein, and bile duct, were subjected to 45 min of hepatic ischemia followed by 60 min reperfusion period. Montelukast (10 mg/kg; i.p.) was administered 15 min prior to ischemia and immediately before reperfusion period. At the end of the reperfusion period, the rats were killed by decapitation. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) activity, and proinflammatory cytokines (TNF-alpha and IL-1beta) were determined in blood samples. Malondialdehyde (MDA), and glutathione (GSH) levels and myeloperoxidase (MPO) and Na+, K+-ATPase activities were determined in the liver tissue samples while formation of reactive oxygen species was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Tissues were also analyzed histologically. Serum ALT, AST, and LDH activities were elevated in the I/R group, while this increase was significantly decreased by montelukast treatment. Hepatic GSH levels and Na+, K+-ATPase activity, significantly depressed by I/R, were elevated back to control levels in montelukast-treated I/R group. Furthermore, increases in tissue luminol and lucigenin CL, MDA levels, and MPO activity due to I/R injury were reduced back to control levels with montelukast treatment. Since montelukast administration alleviated the I/R-induced liver injury and improved the hepatic structure and function, it seems likely that montelukast with its anti-inflammatory and antioxidant properties may be of potential therapeutic value in protecting the liver against oxidative injury due to ischemia-reperfusion.

Betulinic acid protects against ischemia/reperfusion-induced renal damage and inhibits leukocyte apoptosis.

The possible protective effect of betulinic acid on renal ischemia/reperfusion (I/R) injury was studied. Wistar Albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Betulinic acid (250 mg/kg, i.p.) or saline was administered at 30 min prior to ischemia and immediately before the reperfusion. Creatinine, blood urea nitrogen (BUN), lactate dehydrogenase (LDH) and TNF-alpha as well as the oxidative burst of neutrophil and leukocyte apoptosis were assayed in blood samples. Malondialdehyde (MDA), glutathione (GSH) levels, Na(+), K(+)-ATPase and myeloperoxidase (MPO) activities were determined in kidney tissue which was also analysed microscopically. I/R caused significant increases in blood creatinine, BUN, LDH and TNF-alpha. In the kidney samples of the I/R group, MDA levels and MPO activity were increased significantly, however, GSH levels and Na(+), K(+)-ATPase activity were decreased. Betulinic acid ameliorated the oxidative burst response to both formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol 12-myristate 13-acetate (PMA) stimuli, normalized the apoptotic response and most of the biochemical indices as well as histopathological alterations induced by I/R. In conclusion, these data suggest that betulinic acid attenuates I/R-induced oxidant responses, improved microscopic damage and renal function by regulating the apoptotic function of leukocytes and inhibiting neutrophil infiltration.

Evaluation of gadolinium pre-treatment with or without splenectomy in the setting of renal ischemia reperfusion injury in rats.

INTRODUCTION: This study aims to investigate gadolinium chloride (Gd) pre-treatment with/without splenectomy (Splx) in the setting of renal ischemia/reperfusion (IR) injury in rats. MATERIALS AND METHODS: Under anesthesia, male Wistar albino rats with or without splenectomized (Splx) were right nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 3 h of reperfusion. Gadolinium chloride (10 mg kg(-1)) or saline was administered 24 hours prior to ischemia via penile vein. Right nephrectomy and intravenous saline administration was performed in the control group. At the end of the reperfusion period, following decapitation, kidney samples were taken for histological examination or determination of renal malondialdehyde (MDA) and glutathione (GSH) levels and myeloperoxidase (MPO) and Na(+)-K(+) ATPase activities. Creatinine, blood urea nitrogen (BUN), lactate dehydrogenase (LDH), TNF-alpha, and IL-1 beta were assayed in the serum samples. RESULTS: Ischemia/reperfusion caused significant increases in the serum TNF-alpha, IL-1 beta, BUN, creatinine, AST, ALT, LDH, and tissue MDA levels and MPO activity, while either Gd pre-treatment or Splx decreased these parameters significantly. On the other hand, IR induced a decrease in the tissue GSH, and Na(+)-K(+) ATPase activity was restored by both gadolinium and Splx. Furthermore, histopathological alterations induced by IR were also reversed. CONCLUSION: The extent of renal IR injury depends on the pro-inflammatory cytokine response. Gd pre-treatment decreases macrophage-derived cytokine secretion and thereby effectively limits the extent of renal IR injury in rats similar to Splx. Further studies needed to define an optimal way of decreasing macrophage-derived cytokine release due to the clinical limitations of Gd.

Resveratrol protects against irradiation-induced hepatic and ileal damage via its anti-oxidative activity.

The present study was undertaken to determine whether resveratrol (RVT) could ameliorate ionizing radiation-induced oxidative injury. After a 10-days pre-treatment with RVT (10 mg/kg/day p.o.), rats were exposed to whole-body IR (800 cGy) and the RVT treatment was continued for 10 more days after the irradiation. Irradiation caused a significant decrease in glutathione level, while malondialdehyde levels, myeloperoxidase activity and collagen content were increased in the liver and ileum tissues. Similarly, plasma lactate dehydrogenase and pro-inflammatory cytokine levels, 8-hydroxy-2'-deoxyguanosine and leukocyte apoptosis were elevated, while antioxidant-capacity was reduced in the irradiated rats as compared with the control group. Furthermore, Na(+), K(+)-ATPase activity was inhibited and DNA fragmentation was increased in the ileal tissues. Resveratrol treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. In conclusion, supplementing cancer patients with adjuvant therapy of resveratrol may have some benefit for a more successful radiotherapy.

Melatonin improves cardiovascular function and ameliorates renal, cardiac and cerebral damage in rats with renovascular hypertension.

The effect of melatonin was investigated in an angiotensin II-dependent renovascular hypertension model in Wistar albino rats by placing a renal artery clip (two-kidney, one-clip; 2K1C), while sham rats did not have clip placement. Starting either on the operation day or 3 wk after the operation, the rats received melatonin (10 mg/kg/day) or vehicle for the following 6 wk. At the end of the nineth week, after blood pressure (BP) and echocardiographic recordings were obtained, plasma samples were obtained to assay lactate dehydrogenase (LDH), creatine kinase (CK), antioxidant capacity (AOC), asymmetric dimethylarginine (ADMA), and nitric oxide (NOx) levels. In the kidney, heart and brain tissues, malondialdehyde (MDA) and glutathione (GSH) levels, superoxide dismutase (SOD), catalase (CAT), myeloperoxidase (MPO) and Na(+)-K(+) ATPase activities were determined. 2K1C caused an increase in BP and left ventricular (LV) dysfunction. In hypertensive animals LDH, CK, ADMA levels were increased in plasma with a concomitant reduction in AOC and NOx. Moreover, hypertension caused a significant decrease in tissue SOD, CAT, and Na(+), K(+)-ATPase activities and glutathione content, while MDA levels and MPO activity were increased in all studied tissues. On the other hand, both melatonin regimens significantly reduced BP, alleviated oxidative injury and improved LV function. In conclusion, melatonin protected against renovascular hypertension-induced tissue damage and improved cardiac function presumably due to both its direct antioxidant and receptor-dependent actions, suggesting that melatonin may be of therapeutic use in preventing oxidative stress due to hypertension.

Punica granatum peel extract protects against ionizing radiation-induced enteritis and leukocyte apoptosis in rats.

Radiation-induced enteritis is a well-recognized sequel of therapeutic irradiation. Therefore we examined the radioprotective properties of Punica granatum peel extract (PPE) on the oxidative damage in the ileum. Rats were exposed to a single whole-body X-ray irradiation of 800 cGy. Irradiated rats were pretreated orally with saline or PPE (50 mg/kg/day) for 10 days before irradiation and the following 10 days, while control rats received saline or PPE but no irradiation. Then plasma and ileum samples were obtained. Irradiation caused a decrease in glutathione and total antioxidant capacity, which was accompanied by increases in malondialdehyde levels, myeloperoxidase activity, collagen content of the tissue with a concomitant increase 8-hydroxy-2'-deoxyguanosine (an index of oxidative DNA damage). Similarly, pro-inflammatory cytokines (TNF-alpha, IL-1beta and IL-6) and lactate dehydrogenase were elevated in irradiated groups as compared to control. PPE treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Furthermore, flow cytometric measurements revealed that leukocyte apoptosis and cell death were increased in irradiated animals, while PPE reversed these effects. PPE supplementation reduced oxidative damage in the ileal tissues, probably by a mechanism that is associated with the decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms. Adjuvant therapy of PPE may have a potential to support a successful radiotherapy by protecting against radiation-induced enteritis.

Resveratrol treatment protects against doxorubicin-induced cardiotoxicity by alleviating oxidative damage.

The possible protective effects of resveratrol (RVT) against cardiotoxicity were investigated in Wistar albino rats treated with saline, saline+doxorubicin (DOX; 20 mg/kg) or RVT (10 mg/kg)+DOX. Blood pressure and heart rate were recorded on the 1st week and on the 7th week, while cardiomyopathy was assessed using transthoracic echocardiography before the rats were decapitated. DOX-induced cardiotoxicity resulted in decreased blood pressure and heart rate, but lactate dehydrogenase, creatine phosphokinase, total cholesterol, triglyceride, aspartate aminotransferase and 8-OHdG levels were increased in plasma. Moreover, DOX caused a significant decrease in plasma total antioxidant capacity along with a reduction in cardiac superoxide dismutase, catalase and Na+,K+-ATPase activities and glutathione contents, while malondialdehyde, myelopreoxidase activity and the generation of reactive oxygen species were increased in the cardiac tissue. On the other hand, RVT markedly ameliorated the severity of cardiac dysfunction, while all oxidant responses were prevented; implicating that RVT may be of therapeutic use in preventing oxidative stress due to DOX toxicity.

Ghrelin improves burn-induced multiple organ injury by depressing neutrophil infiltration and the release of pro-inflammatory cytokines.

Mechanisms of burn-induced skin and remote organ injury involve oxidant generation and the release of pro-inflammatory cytokines. In this study the possible antioxidant and anti-inflammatory effects of ghrelin were evaluated in a rat model of thermal trauma. Wistar albino rats were exposed to 90 degrees C bath for 10 s to induce thermal trauma. Ghrelin, was administered subcutaneously (10 ng/kg/day) after the burn injury and repeated twice daily. Rats were decapitated at 6 h and 48 h after burn injury and blood was collected for the analysis of pro-inflammatory cytokines (TNF-alpha and IL-1beta), lactate dehydrogenase (LDH) activity and antioxidant capacity (AOC). In skin, lung and stomach tissue samples malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) and Na(+)-K(+)-ATPase activity were measured in addition to the histological analysis. DNA fragmentation ratio in the gastric mucosa was also evaluated. Burn injury caused significant increase in both cytokine levels, and LDH activity, while plasma AOC was found to be depleted after thermal trauma. On the other hand, in tissue samples the raised MDA levels, MPO activity and reduced GSH levels, Na(+)-K(+)-ATPase activity due to burn injury were found at control levels in ghrelin-treated groups, while DNA fragmentation in the gastric tissue was also reduced. According to the findings of the present study, ghrelin possesses a neutrophil-dependent anti-inflammatory effect that prevents burn-induced damage in skin and remote organs and protects against oxidative organ damage.

Protective effect of resveratrol against naphthalene-induced oxidative stress in mice.

OBJECTIVE: This investigation confirms the role of free radicals in naphthalene-induced toxicity and elucidates the mechanism of resveratrol (RVT). METHODS: Both male and female BALB-c mice were administered with naphthalene (100 mg/kg, i.p.) for 30 days, either along with saline or along with RVT (10mg/kg, orally). At the end of the experiment, following treatment and sacrifice of animals by decapitation, lung, liver and kidney tissue samples were taken for histological examination or determination of malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity and collagen contents. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine levels and lactate dehydrogenase (LDH) activity were measured in the serum samples, while TNF-alpha, IL-beta, IL-6 and total antioxidant capacity (AOC) were assayed in plasma samples. RESULTS: Naphthalene administration caused a significant decrease in tissue GSH and plasma AOC, which was accompanied with significant increases in tissue MDA and collagen levels and MPO activity. Moreover, the pro-inflammatory mediators (TNF-alpha, IL-beta, IL-6), LDH activity, AST, ALT, creatinine and BUN levels were significantly increased in the naphthalene group. On the other hand, RVT treatment reversed all these biochemical indices as well as histopathological alterations induced by naphthalene. CONCLUSIONS: Oxidative mechanisms play an important role in naphthalene-induced tissue damage, and RVT, by inhibiting neutrophil infiltration, balancing oxidant-antioxidant status, and regulating the generation of inflammatory mediators, ameliorates oxidative organ injury due to naphthalene toxicity.

Grape seed extract treatment reduces hepatic ischemia-reperfusion injury in rats.

This study was designed to determine the possible protective effect of grape seed extract (GSE), a widely used antioxidant dietary supplement, on hepatic ischemia/reperfusion (I/R) injury. Wistar albino rats were subjected to 45 min of hepatic ischemia, followed by a 60 min reperfusion period. GSE was administered in a dose of 50 mg/kg/day orally for 15 days before I/R injury and repeated before the reperfusion period. Liver samples were taken for histological examination or determination of hepatic malondialdehyde (MDA), glutathione (GSH) and myeloperoxidase (MPO) activity. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were determined to assess liver functions. Lactate dehydrogenase (LDH) and cytokines (TNF-alpha and IL-1 beta) were also assayed in serum samples for the evaluation of generalized tissue damage. Ischemia/reperfusion caused a significant decrease in hepatic GSH, and significant increases in MDA level, and MPO activity. Serum AST and ALT levels, as well as LDH activity and plasma TNF-alpha and IL-1beta levels were also elevated in the I/R group. Treatment with GSE reversed all these biochemical parameters as well as histological alterations induced by I/R. In conclusion, GSE reduced I/R-induced organ injury through its ability to balance the oxidant-antioxidant status, to inhibit neutrophil infiltration and to regulate the release of inflammatory mediators.

Antioxidant effect of alpha-lipoic acid against ethanol-induced gastric mucosal erosion in rats.

BACKGROUND/AIMS: This investigation elucidates the role of free radicals in ethanol-induced gastric mucosal erosion and the protective effect of lipoic acid. METHODS: After overnight fasting, Wistar albino rats were orally treated with 1 ml of absolute ethanol to induce gastric erosion. Lipoic acid (100 mg/kg) was given orally for 3 days before ethanol administration. Mucosal damage was evaluated 1 h after ethanol administration by macroscopic examination and histological analysis. Additional tissue samples were taken for measurement of malondialdehyde, glutathione (GSH), and myeloperoxidase activity. Production of reactive oxidants and oxidant-induced DNA fragmentation and Na(+),K(+)-ATPase activity were also assayed in the tissue samples. RESULTS: Generation of reactive oxygen species and lipid peroxidation associated with neutrophil infiltration play an important role in the pathogenesis of gastric mucosal damage induced by ethanol. Furthermore, oxidants depleted tissue GSH stores and impaired membrane structure as Na(+),K(+)-ATPase activity was inhibited. On the other hand, lipoic acid treatment reversed all these biochemical indices as well as the histopathological changes induced by ethanol. CONCLUSION: These data suggest that lipoic acid administration effectively counteracts the deleterious effect of ethanol-induced gastric mucosal injury and attenuates gastric damage through its antioxidant effects.

Alpha-lipoic acid protects against renal ischaemia-reperfusion injury in rats.

1. Oxygen free radicals are important components involved in the pathophysiological processes observed during ischaemia-reperfusion (I/R). The present study was designed to assess the possible protective effect of alpha-lipoic acid (ALA) on renal I/R injury. 2. Wistar albino rats were unilaterally nephrectomized and subjected to 45 min renal pedicle occlusion followed by 24 h reperfusion. Saline or ALA (100 mg/kg, i.p.) was administered 15 min prior to ischaemia and immediately before the reperfusion period. At the end of 24 h, rats were decapitated and trunk blood was collected. Creatinine, blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) activity were measured in serum samples, whereas tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, 8-hydroxydeoxyguanosine (8-OHdG) and total anti-oxidant capacity (AOC) were assayed in plasma samples. 3. Kidney samples were taken for the determination of tissue malondialdehyde (MDA) and glutathione (GSH) levels, as well as Na(+)/K(+)-ATPase and myeloperoxidase (MPO) activity. The formation of reactive oxygen species in renal tissue samples was monitored using a chemiluminescence (CL) technique with luminol and lucigenin probes. Oxidant-induced tissue fibrosis was determined by tissue collagen content and the extent of tissue injury was analysed microscopically. 4. Ischaemia-reperfusion caused a significant increases in blood creatinine, BUN, LDH, IL-1beta, IL-6, TNF-alpha and 8-OHdG, whereas AOC was decreased. In kidney samples from the I/R group, MDA, MPO, collagen and CL levels were found to be increased significantly; however, glutathione levels and Na(+)/K(+)-ATPase activity were decreased. Conversely, ALA treatment reversed all these biochemical indices, as well as histopathological alterations induced by I/R. 5. In conclusion, these data suggest that ALA reverses I/R-induced oxidant responses and improves microscopic damage and renal function. Thus, it seems likely that ALA protects kidney tissues by inhibiting neutrophil infiltration, balancing the oxidant-anti-oxidant status and regulating the generation of inflammatory mediators.

Pomegranate peel extract prevents liver fibrosis in biliary-obstructed rats.

Punica granatum L. (pomegranate) is a widely used plant that has high nutritional value. The aim of this study was to assess the effect of chronic administration of pomegranate peel extract (PPE) on liver fibrosis induced by bile duct ligation (BDL) in rats. PPE (50 mg kg(-1)) or saline was administered orally for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage. Proinflammatory cytokines (tumor necrosis factor-alpha and interleukin 1 beta) in the serum and antioxidant capacity (AOC) were measured in plasma samples. Samples of liver tissue were taken for measurement of hepatic malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence assay. Serum AST, ALT, LDH and cytokines were elevated in the BDL group compared with the control group; this increase was significantly decreased by PPE treatment. Plasma AOC and hepatic GSH levels were significantly depressed by BDL but were increased back to control levels in the PPE-treated BDL group. Increases in tissue MDA levels and MPO activity due to BDL were reduced back to control levels by PPE treatment. Similarly, increased hepatic collagen content in the BDL rats was reduced to the level of the control group with PPE treatment. Thus, chronic PPE administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic structure and function. It therefore seems likely that PPE, with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver from fibrosis and oxidative injury due to biliary obstruction.

Montelukast reduces ischaemia/reperfusion-induced bladder dysfunction and oxidant damage in the rat.

The present study aimed to investigate the possible beneficial effects of the cysteinyl leukotriene-1 receptor antagonist montelukast on contractility and oxidant damage after ischaemia/reperfusion (I/R) of rat urinary bladder. The abdominal aorta of Sprague-Dawley rats was occluded to induce I/R. Montelukast (10 mg kg(-1)) or saline was administered intraperitoneally before I/R. In the sham-operated group, the abdominal aorta was left intact and the animals were treated with montelukast or saline. After decapitation, the bladder was removed and the tissue was either used for functional studies or stored for biochemical assays. In the I/R group, the isometric contractile responses of the bladder strips to carbachol (10(-8)-10(-4) M) were lower than those of the control group and were reversed by treatment with montelukast. Lipid peroxidation and myeloperoxidase activity of the bladder tissues in the I/R group were greater than in the sham-operated group. Montelukast treatment in the I/R group decreased these parameters compared with I/R alone. Similarly, the significant decrease in tissue glutathione level in the I/R group compared with controls was also prevented by montelukast. Treatment with montelukast almost completely reversed the low contractile responses of rat urinary bladder to carbachol and prevented oxidative tissue damage following I/R.

Resveratrol improves ifosfamide-induced Fanconi syndrome in rats.

Regarding the mechanisms of ifosfamide (IFO)-induced urinary toxicity, several hypotheses have been put forward, among which oxidative stress and depletion of glutathione are suggested. This investigation elucidates the role of free radicals in IFO-induced toxicity and the protection by resveratrol, a natural phytoalexin. Wistar albino rats were injected intraperioneally with saline (0.9% NaCl; control), saline+resveratrol (RVT; 10 mg/kg/day), ifosfamide (IFO; 50 mg/kg/day) or IFO+RVT for 5 days. Urine was collected for 24 h during the 5th day, and at the 120th h after the first injections, animals were killed by decapitation and trunk blood was collected. Lactate dehydrogenase (LDH) activity, total antioxidant capacity (AOC) and pro-inflammatory cytokines TNF-alpha, IL-beta and IL-6 were assayed in plasma samples. Kidney and bladder tissues were obtained for biochemical and histological analysis. Formation of reactive oxygen species in the tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. The results demonstrated that IFO induced a Fanconi syndrome characterized by increased urinary sodium, phosphate, glucose and protein, along with increased serum creatinine and urea levels. On the other hand, RVT markedly ameliorated the severity of renal dysfunction induced by IFO. Furthermore IFO caused a significant decrease in plasma AOC, which was accompanied with significant increases in the levels of the pro-inflammatory mediators and LDH activity, while RVT treatment reversed all these biochemical indices. In the saline-treated IFO group, glutathione levels were decreased significantly, while the malondialdehyde levels, myeloperoxidase activity and collagen content were increased in both tissues, which were in parallel with the increases in CL values. In the RVT-treated IFO group, all of these oxidant responses were prevented significantly. Our results suggest that IFO causes oxidative damage in the renal and bladder tissues and resveratrol, via its antioxidant effects, protects these tissues. Therefore, its therapeutic role in preventing the development of chemotherapeutic drug-induced major toxicity in the urinary system requires further elucidation.