The Effects of Spironolactone in Preventing Bile Duct Ligation-induced Hepatitis in A Rat Model.

Cholestasis is associated with the accumulation of bile acids and bilirubin in the hepatocytes and leads to liver injury. Pregnane X Receptor (PXR) coordinates protective hepatic responses to toxic stimuli, and this receptor was reported to stimulate bile secretion by increasing MRP2 expression. Since PXR activators were reported to be anti-inflammatory in the liver, PXR was proposed as a drug target for the treatment of chronic inflammatory liver diseases. We investigated the potential protective effect of spironolactone (SPL), an enzyme inducer, in hepatotoxicity induced by bile duct ligation in rats. Wistar Albino (250-300 g) rats were divided into the control group and the bile duct ligated (BDL) group. BDL group was divided into three subgroups; following BDL, for 3 days, the first group received propylene glycol (vehicle of SPL) (blinded), the second subgroup received spironolactone (SPL) (200 mg/kg oral), and the third subgroup received SPL for 3 days, starting 3 days after the bile duct ligation, in order to investigate if it has a healing effect after hepatitis had developed. The control group was sham-operated and received saline. At the end of the experiment, blood and tissue samples were collected. Serum TNF-α, NF-ĸB, bilirubin, IL-6 levels, ALT, AST, ALP activities and tissue MPO activity and oxidant damage increased after the bile duct ligation was significantly decreased following SPL administration. PXR and MRP2 activity showed an increase in the hepatocytes as a result of the treatment. In conclusion, it was observed that SPL administration significantly decreases liver inflammation and damage related to BDL.

Protective effect of bromelain on corrosive burn in rats.

INTRODUCTION: In some cases, the tongue and oesophagus tissues are damaged by the corrosive burn. Surgical interventions may cause scar formation, and severe burns treatment methods are limited. This study aims to investigate bromelain, a phytotherapeutic product, on the corrosive burn as a non-surgical option and as an adjunctive therapy, insofar as the treatment of corrosive wounds is not limited only to the treatment of oxidative stress and inflammatory reactions. METHODS: On the tongues of Wistar albino rats, chemically produced oral ulcers were created by topical application of NaOH (40%) solution, and in the distal oesophagus same mixture was applied to produce a corrosive oesophageal burn. For a week, they were treated orally by bromelain (100 mg/kg/day) or saline solution. At the end of seven days, animals were decapitated to remove the tongue and oesophagus, and blood samples were collected to obtain serum. Myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), interleukin-1 beta (IL-1ß) and tumour necrosis factor-alpha (TNF-α) concentrations were measured in serum, and luminol and lucigenin chemiluminescence (CL) were measured in tissue samples. RESULTS: MDA and CL values were significantly increased, and GSH levels in tissue significantly decreased due to the corrosive burns. Saline treated corrosive burn group measured higher in the serum cytokines in according to the control group. CONCLUSIONS: Bromelain administration decreased oxidant and inflammatory parameters and increased antioxidant levels in NaOH-induced corrosive burns. Thus, we concluded that bromelain may protect the tongue and oesophagus tissues with its anti-inflammatory and antioxidant effects.

Protective effects of spironolactone against hepatic ischemia/reperfusion injury in rats.

OBJECTIVES: In the present study, it was aimed to study the antioxidant effects of spironolactone (SPL) to determine its possible protective effects in hepatic ischemia reperfusion injury. MATERIAL AND METHODS: Hepatic artery, portal vein, and bile duct of Wistar albino rats were clamped for 45 minutes under anesthesia to form an ischemia period. Then reperfusion was allowed and the rats were decapitated 60 minutes later. SPL (20 mg/kg, p.o.) or SF was orally administered for 30 minutes before ischemia. Rats in the control arm underwent sham surgery and were administered isotonic saline. Liver function was studied by measuring aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-alpha (TNF-α), and interleukin 1beta (IL-1ß) levels. Malondialdehyde (MDA), glutathione (GSH), luminol, and lucigenin levels, myeloperoxidase (MPO) and Na+-K+-ATPase enzyme activities were analyzed to study tissue injury under light microscope. RESULTS: While IR increased AST, ALT, TNF-α, and IL-1ß levels and MDA, luminol, and lusigenin levels and MPO activities, it caused a decrease in GSH levels and Na+K+-ATPase activity. Spironolactone administration significantly improved these values. CONCLUSION: Protective effects of SPL against ischemia/reperfusion injury via various mechanisms suggest that this agent may become a novel treatment agent in clinical practice.

Effect of moderate or high intensity exercise on hypothyroid rats exposed to acute stress.

BACKGROUND: There are contradictory results about stress response in hypothyroidism and in exercising with variant intensities. We aimed to investigate the potential anxiolytic and protective effects of different intensities of exercise on acute psychological stress in hypothyroidism. METHODS: Rats (N.=48) were divided as sedentary, moderate intensity (MIE) and high intensity exercise (HIE) groups. Rats were administered intraperitoneally with 6-n-propyl-2-thiouracil (PTU, 10 mg/kg) for 15 days to induce hypothyroidism. Starting by the 3rd week, treadmill exercise was performed moderately (30 min/day) or at high intensity (60 min/day) for 6 weeks, 5 days/week. At the end of the 8th week, exposure to water avoidance stress was used for induction of acute stress. Anxiety-like behavior was determined by holeboard test before and after stress inductions. Serum IL-1ß and IL-6 assays, and myeloperoxidase activity (MPO), malondialdehyde (MDA), and glutathione (GSH) measurements, and histological analysis of heart, liver, stomach and small intestine were made. RESULTS: All groups showed increased anxiety-like behavior following acute stress induction. After acute stress induction, increased MPO and MDA levels in heart and elevated MPO activity in liver were inhibited in PTU-treated HIE group. In MIE rats, increased MPO and declined GSH levels of the gastric tissue and small intestine, and elevated MDA levels of gastric tissue were reversed in PTU-treated MIE group. Major histological changes that occurred by both intensities of exercise under stress condition were improved by PTU. CONCLUSIONS: Our results indicate that hypothyroid state may be protective against stress- and exhaustive exercise-induced oxidative damage.

Inhibition of 5-lipoxygenase by zileuton in a rat model of myocardial infarction.

OBJECTIVE: The goal of the present study was to investigate the effects of 5-lipoxygenase (5-LOX) inhibition, alone and with cyclooxygenase (COX) inhibitors, on inflammatory parameters and apoptosis in ischemia/reperfusion (I/R)-induced myocardial damage in rats. For this purpose, zileuton, a selective and potent inhibitor of 5-LOX, resulting in suppression leukotriene production, was used. METHODS: Male Wistar rats (200-250 g; n=12 per group) were used in the study. I/R was performed by occluding the left coronary artery for 30 minutes and 2 hours of reperfusion of the heart. Experimental groups were I/R group, sham I/R group, zileuton (5 mg/kg orally, twice daily)+I/R group, zileuton+indomethacin (5 mg/kg intraperitoneally)+I/R group, zileuton+ketorolac (10 mg/kg subcutaneously)+I/R group, and zileuton+nimesulide (5 mg/kg subcutaneously)+I/R group. Following I/R, blood samples were collected to measure tumor necrosis factor alpha (TNF-α), and left ventricles were excised for evaluation of microscopic damage; malondialdehyde (MDA), glutathione, nuclear factor (NF)-κB assays; and evaluation of apoptosis. RESULTS: Left ventricle MDA in I/R group was higher compared to sham group; however, it did not show significant change with zileuton. Although tissue injury in I/R group was less severe in all treatment groups, it was not statistically significant. NF-κB H-score and apoptotic index, which were higher in I/R group compared to sham I/R, were decreased with application of zileuton (H-score: p<0.01; apoptotic index: p<0.001). Zileuton had no significant effect on increased serum TNF-α levels in I/R group. CONCLUSION: 5-LOX inhibition in rat myocardial infarction model attenuated increased left ventricle NF-κB expression and apoptosis and these actions were not modulated by COX inhibitors.

The role of cholinergic anti-inflammatory pathway in acetic acid-induced colonic inflammation in the rat.

The "cholinergic anti-inflammatory pathway" provides neurological modulation of cytokine synthesis to limit the magnitude of the immune response. This study aimed to evaluate the impact of the cholinergic anti-inflammatory pathway on the extent of tissue integrity, oxidant-antioxidant status and neutrophil infiltration to the inflamed organ in a rat model of acetic acid-induced colitis. Colitis was induced by intrarectal administration of 5% acetic acid (1ml) to Sprague-Dawley rats (200-250g; n=7-8 per group). Control group received an equal volume of saline intrarectally. The rats were treated with either nicotine (1mg/kg/day) or huperzine A (0.1mg/kg/day) intraperitoneally for 3 days. After decapitation, the distal colon was scored macroscopically and microscopically. Tissue samples were used for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. Formation of reactive oxygen species was monitored by using chemiluminescence (CL). Nuclear factor (NF)-κB expression was evaluated in colonic samples via immunohistochemical analysis. Trunk blood was collected for the assessment of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-10, resistin and visfatin levels. Both nicotine and huperzine A reduced the extent of colonic lesions, increased colonic MDA level, high MPO activity and NF-κB expression in the colitis group. Elevation of serum IL-1ß level due to colitis was also attenuated by both treatments. Additionally, huperzine A was effective to reverse colitis-induced high lucigenin-enhanced CL values and serum TNF-α levels. Colitis group revealed decreased serum visfatin levels compared to control group which was completely reversed by nicotine. In conclusion, modulation of the cholinergic system either by nicotine or ACh esterase inhibition improved acetic acid-induced colonic inflammation as confirmed by macroscopic and microscopic examination and biochemical assays.

Matrix Metalloproteinase-9 Level and Gene Polymorphism in Sleep Disordered Breathing Patients with or without Cardiovascular Disorders.

OBJECTIVE: Obstructive sleep apnea syndrome (OSAS) is associated with increased cardiovascular morbidity and mortality. We aimed to investigate the matrix metalloproteinase-9 (MMP-9) level and MMP-9 gene polymorphism in sleep apnea patients with or without cardiovascular disease. STUDY DESIGN: Case-control study. MATERIAL AND METHODS: Two hundred nine patients [Mean age (±SD), 47 (±12) yrs; M/F, 170/39] diagnosed with sleep-disordered breathing were included in the study. Serum MMP-9 level was performed using enzyme-linked immunosorbant assay (ELISA) and MMP-9 gene polymorphism with polymerase chain reaction-restriction fragment length polymorphism. We divided the patient group into two subgroups: (1) patients with confirmed cardiovascular disease, i.e. CV-P Group and (2) patients without cardiovascular disease, CV-N Group. We compared all parameters between the two groups. RESULTS: There were 56 OSAS patients with cardiovascular disorder (CV-positive group) and 153 OSAS patients without cardiovascular disorder (CV-negative group). CC, CT and TT genotype distributions between groups were similar [31 (55%), 25 (45%), 0 (0%) vs 88 (57%), 61 (40%), 4 (3%); respectively, p>0.05]. MMP-9 level was significantly higher in CV-P patients (442.7±139.3 pg/mL) than in CV-N patients (364.4±165.0 pg/mL; p=0.0018). CONCLUSION: Our results showed that the presence of MMP-9 polymorphism was not associated with cardiovascular disease. MMP-9 level was higher in OSAS patients with cardiovascular disorders than without cardiovascular disorders. Finally, MMP-9 genotype was not associated with serum MMP-9 levels.

The anti-inflammatory and neuroprotective effects of ghrelin in subarachnoid hemorrhage-induced oxidative brain damage in rats.

To elucidate the putative neuroprotective effects of ghrelin in subarachnoid hemorrhage (SAH)-induced brain injury, Wistar albino rats (n = 54) were divided into sham-operated control, saline-treated SAH, and ghrelin-treated (10 microg/kg/d IP) SAH groups. The rats were injected with blood (0.3 mL) into the cisterna magna to induce SAH, and were sacrificed 48 h after the neurological examination scores were recorded. In plasma samples, neuron-specific enolase (NSE), S-100beta protein, TNF-alpha, and IL-1beta levels were evaluated, while forebrain tissue samples were taken for the measurement of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species levels, myeloperoxidase (MPO), Na(+)-K(+)-ATPase activity, and DNA fragmentation ratio. Brain tissue samples containing the basilar arteries were obtained for histological examination, while cerebrum and cerebellum were removed for the measurement of blood-brain barrier (BBB) permeability and brain water content. The neurological scores were impaired at 48 h after SAH induction, and SAH caused significant decreases in brain GSH content and Na(+)-K(+)-ATPase activity, and increases in chemiluminescence, MDA levels, and MPO activity. Compared with the control group, the protein levels of NSE, S-100beta, TNF-alpha, and IL-1beta in plasma were also increased, while ghrelin treatment prevented all SAH-induced alterations observed both biochemically and histopathologically. The results demonstrate that ghrelin alleviates SAH-induced oxidative brain damage, and exerts neuroprotection by maintaining a balance in oxidant-antioxidant status, by inhibiting proinflammatory mediators, and preventing the depletion of endogenous antioxidants evoked by SAH.

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.

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.

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.

Silymarin, the antioxidant component of Silybum marianum, prevents sepsis-induced acute lung and brain injury.

BACKGROUND: Sepsis is associated with enhanced generation of reactive oxygen species, which leads to multiple organ dysfunctions. Based on the potent antioxidant effects of silymarin, we investigated the putative protective role of silymarin against sepsis-induced oxidative damage in lung and brain tissues. MATERIALS AND METHODS: Sepsis was induced by cecal ligation and perforation (CLP). Sham and CLP groups received either vehicle or silymarin (50 mg/kg, p.o.) or 150 mg/kg i.p. N-acetylcysteine (NAC) for 10 days prior and immediately after the operation. Six hours after the surgery, rats were decapitated and blood was collected for the measurement of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta [IL-1 beta], and IL-6) levels, lactate dehydrogenase activity, and total antioxidant capacity. Lung and brain samples were taken for the measurement of malondialdehyde and glutathione levels, myeloperoxidase activity, thromboplastic activity, and also for histological assessment. Formation of reactive oxygen species in tissue samples was monitored by using chemiluminescence technique with luminol and lusigenin probe. RESULTS: Sepsis increased serum TNF-alpha, IL-1 beta, IL-6 levels, and lactate dehydrogenase activity and decreased total antioxidant capacity. On the other hand, tissue glutathione levels were decreased while malondialdehyde levels and myeloperoxidase activity were increased in both the lung and the brain tissues due to CLP. Furthermore, luminol and lucigenin chemiluminescence were significantly increased in the CLP group, indicating the presence of the oxidative damage. Silymarine and NAC treatment reversed these biochemical parameters and preserved tissue morphology as evidenced by histological evaluation. CONCLUSIONS: Silymarin, like NAC, reduced sepsis-induced remote organ injury, at least in part, through its ability to balance oxidant-antioxidant status, to inhibit neutrophil infiltration, and to regulate the release of inflammatory mediators.

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.

Oxidative renal damage in pyelonephritic rats is ameliorated by montelukast, a selective leukotriene CysLT1 receptor antagonist.

Urinary tract infections may induce severe inflammation, transient impairment in renal function and scar formation, ranging in severity from acute symptomatic pyelonephritis to chronic pyelonephritis, which have a potential to lead to renal failure and death. The present study aimed to investigate the possible protective effect of montelukast, a selective antagonist of cysteinyl leukotriene receptor 1 (leukotriene CysLT1), against Escherichia coli-induced oxidative injury and scarring in renal tissue. Wistar rats were injected 0.1 ml of E. coli (ATCC 25922 10(10) cfu/ml) or saline into left renal medullae. Six rats were assigned as the sham group and were given 0.1 ml 0.9% NaCl. Pyelonephritic rats were treated with either saline or montelukast immediately after surgery and at daily intervals. Twenty-four hours or one week after E. coli injection, rats were decapitated and the kidney samples were taken for histological examination or determination of renal malondialdehyde, glutathione (GSH) levels, myeloperoxidase (MPO) activity, and collagen contents. Formation of reactive oxygen species in renal tissue samples was monitored by using chemiluminescence technique with luminol and lucigenin probes. Creatinine, blood urea nitrogen and lactate dehydrogenase (LDH) activity were measured in the serum samples. E. coli inoculation caused significant increases in malondialdehyde level, MPO activity, chemiluminescence levels and collagen content, while GSH level was decreased in the renal tissues (p<0.05-0.001). On the other hand, serum TNF-alpha, LDH, blood urea nitrogen and serum creatinine levels were elevated in the pyelonephritic rats as compared to control group. Leukotriene CysLT1 receptor antagonist montelukast reversed all these biochemical indices, as well as histopathological alterations, that were induced by acute pyelonephritis. It seems likely that montelukast protects kidney tissue by inhibiting neutrophil infiltration, balancing oxidant-antioxidant status, and regulating the generation of inflammatory mediators suggesting a future role for leukotriene CysLT1 receptor antagonists in the treatment of pyelonephritis.

Melatonin prevents neutrophil-mediated oxidative injury in Escherichia coli-induced pyelonephritis in rats.

Regarding the mechanisms of renal scarring in pyelonephritis, several hypotheses have been put forward, among which oxidative stress is prominent. The present study investigated the possible protective effect of melatonin treatment against Escherichia coli-induced oxidative injury and scarring in renal tissue. For this purpose, 0.1 mL E. coli (ATCC 25922; 10(10) colony-forming units/mL) or saline was injected directly into the renal parenchyma of Wistar rats. Pyelonephritic rats were treated with either saline or melatonin (10 mg/kg) intraperitoneally. Twenty-four hours or 1 wk after E. Coli injection, rats were decapitated and trunk blood samples were collected for BUN, creatinine, tumor necrosis factor-alpha (TNF-alpha) and lactate dehydrogenase (LDH) determination. In kidney samples, histological analysis was performed, and malondialdehyde (MDA), glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents were measured. Formation of reactive oxygen species was monitored using a chemiluminescence (CL) technique. Escherichia Coli inoculation caused a significant reduction in renal GSH levels, which was accompanied by significant increases in MDA levels, MPO activity, CL levels and collagen content of the renal tissues (P < 0.05-0.001). Similarly, serum TNF-alpha and, LDH, BUN and creatinine levels were elevated in the pyelonephritic rats when compared with control animals. Melatonin treatment reversed all these biochemical indices, as well as histopathological alterations induced by acute pyelonephritis. The protective effects of melatonin can be ascribed to its ability to inhibit neutrophil infiltration, to balance the oxidant-antioxidant status, and to regulate the generation of inflammatory mediators, suggesting a future role for melatonin in the treatment of acute pyelonephritis.

Propylthiouracil (PTU)-induced hypothyroidism alleviates burn-induced multiple organ injury.

Oxidative stress has an important role in the development of multiorgan failure after major burn. This study was designed to determine the possible protective effect of experimental hypothyroidism in hepatic and gastrointestinal injury induced by thermal trauma. Sprague Dawley rats were administered saline or PTU (10 mgkg(-1) i.p.) for 15 days, and hypothyroidism was confirmed by depressed serum T(3) and T(4) concentrations. Under brief ether anesthesia, shaved dorsum of rats was exposed to 90 degrees C (burn group) or 25 degrees C (control group) water bath for 10s. PTU or saline treatment was repeated at the 12th hour of the burn. Rats were decapitated 24h after injury and tissue samples from liver, stomach and ileum were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Formation of reactive oxygen species in tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Tissues were also examined microscopically. Tumor necrosis factor (TNF)-alpha and lactate dehydrogenase (LDH) were assayed in serum samples. Severe skin scald injury (30% of total body surface area) caused a significant decrease in GSH level, which was accompanied with significant increases in MDA level, MPO activity, CL levels and collagen content of the studied tissues (p<0.05-0.001). Similarly, serum TNF-alpha and LDH were elevated in the burn group as compared to control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by thermal trauma. Our results suggest that PTU-induced hypothyroidism reduces oxidative damage in the hepatic, gastric and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.

Acetaminophen-induced toxicity is prevented by beta-D-glucan treatment in mice.

The protective effect of beta-glucan against oxidative injury caused by acetaminophen was studied in mice liver. BALB-c mice (25-30 g) were pre-treated with beta-d-glucan (50 mg/kg, p.o.) for 10 days and on the 11th day they received an overdose of acetaminophen (900 mg/kg, i.p.). Four hours after the acetaminophen injection, mice were decapitated and their blood was taken to determine serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and tumor necrosis factor-alpha (TNF-alpha) levels. Tissue samples of the liver were taken for histological examination or for the determination of levels of malondialdehyde, an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase activity, an index of tissue neutrophil infiltration. The formation of reactive oxygen species in hepatic tissue samples was monitored by using the chemiluminescence technique with luminol and lucigenin probes. Acetaminophen caused a significant decrease in the GSH level of the tissue, which was accompanied with significant increases in the hepatic luminol and lucigenin chemiluminescence values, malondialdehyde level, MPO activity and collagen content. Similarly, serum ALT, AST levels, as well as LDH and TNF-alpha, were elevated in the acetaminophen-treated group when compared with the control group. On the other hand, beta-d-glucan treatment reversed all these biochemical indices, as well as histopathological alterations that were induced by acetaminophen. In conclusion, these results suggest that beta-d-glucan exerts cytoprotective effects against oxidative injury through its antioxidant properties and may be of therapeutic use in preventing acetaminophen toxicity.

Oxytocin alleviates oxidative renal injury in pyelonephritic rats via a neutrophil-dependent mechanism.

BACKGROUND: Urinary tract infection (UTI) may cause inflammation of the renal parenchyma and may lead to impairment in renal function and scar formation. Oxidant injury and reactive oxygen species (ROS) have been found responsible in the pathogenesis of UTI. The neurohypophyseal hormone oxytocin (OT) facilitates wound healing and is involved in the modulation of immune and inflammatory processes. We investigated the possible therapeutic effects of OT against Escherichia coli induced pyelonephritis in rats both in the acute and chronic setting. METHODS: Twenty-four Wistar rats were injected 0.1 ml solution containing E. coli ATCC 25922 10(10) colony forming units/ml into left renal medullae. Six rats were designed as sham group and were given 0.1 ml 0.9% NaCl. Pyelonephritic rats were treated with either saline or OT immediately after surgery and at daily intervals. Half of the pyelonephritic rats were decapitated at the 24th hour of E. coli infection, and the rest were followed for 7 days. Renal function tests (urea, creatinine), systemic inflammation markers [lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-alpha)] and renal tissue malondialdehyde (MDA) as an end product of lipid peroxidation, glutathione (GSH) as an antioxidant parameter and myeloperoxidase (MPO) as an indirect index of neutrophil infiltration were studied. RESULTS: Blood urea, creatinine, and TNF-alpha levels were increased, renal tissue MDA and MPO levels were elevated and GSH levels were decreased in both of the pyelonephritic (acute and chronic) rats. All of these parameters and elevation of LDH at the late phase were all reversed to normal levels by OT treatment. CONCLUSION: OT alleviates oxidant renal injury in pyelonephritic rats by its anti-oxidant actions and by preventing free radical damaging cascades that involves excessive infiltration of neutrophils.

Protective effects of resveratrol against acetaminophen-induced toxicity in mice.

This investigation elucidates the role of free radicals in acetaminophen (AA)-induced toxicity and the possible protection by resveratrol (RVT). BALB-c mice were injected with a single dose of 900mg/kg AA to induce toxicity, while RVT administred in a dose of 30mg/kg i.p. following AA. Mice were sacrificed 4h after AA injection to determine serum ALT, AST and tumor necrosis factor-alpha (TNF-alpha) levels in blood, and glutathione (GSH), malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity and collagen contents in liver tissues. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probe. ALT, AST levels and TNF-alpha were increased significantly after AA treatment, and reduced with RVT. AA caused a significant decrease in GSH levels while MDA levels and MPO activity were increased in liver tissues. On the other hand when RVT administered following AA, depletion of GSH and accumulation of MDA and neutrophil infiltration were reversed back to control. Furthermore increased luminol and lucigenin CL levels in the AA group reduced by RVT treatment. Our results implicate that AA causes oxidative damage in hepatic tissues and RVT, by its potent antioxidant effects protects the liver tissue. These data suggest that RVT may be of therapeutic use in preventing hepatic oxidative injury due to AA toxicity.

Montelukast protects against renal ischemia/reperfusion injury in rats.

BACKGROUND: Oxygen free radicals are important components involved in the pathophysiological processes observed during ischemia/reperfusion (I/R). OBJECTIVE: This study was designed to assess the possible protective effect of montelukast, a selective antagonist of cysteinyl leukotriene receptor 1 (CysLT1), on renal I/R injury. METHODS: Wistar albino rats were unilaterally nephrectomized and subjected to 45 min of renal pedicle occlusion followed by 6 h of reperfusion. Montelukast (10 mgkg(-1), i.p.) or saline was administered at 15 min prior to ischemia and immediately before the reperfusion period. At the end of the reperfusion period, following decapitation, kidney samples were taken for histological examination or for determination of renal malondialdehyde (MDA), an end product of lipid peroxidation; glutathione (GSH), a key antioxidant; and myeloperoxidase (MPO) activity, an index of tissue neutrophil infiltration. Formation of reactive oxygen species in renal tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Creatinine, blood urea nitrogen and lactate dehydrogenase (LDH) activity were measured in the serum samples, while leukotriene B4, TNF-alpha, IL-beta, IL-6 and total antioxidant capacity (AOC) were assayed in plasma samples. RESULTS: Ischemia/reperfusion caused a significant decrease in renal GSH and plasma AOC, which was accompanied with significant increases in MDA level, MPO activity, and CL levels of the renal tissue concomitant with increased levels of the pro-inflammatory mediators, LDH activity, creatinine and BUN. On the other hand, montelukast treatment reversed all these biochemical indices as well as histopathological alterations induced by I/R. CONCLUSIONS: CysLT1 receptor antagonist montelukast reversed I/R-induced oxidant responses, improved microscopic damage and renal function. It seems likely that montelukast protects kidney tissue by inhibiting neutrophil infiltration, balancing oxidant-antioxidant status, and regulating the generation of inflammatory mediators.