Gazi Contuk

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.

Leptin ameliorates burn-induced multiple organ damage and modulates postburn immune response in rats

The present study was designed to determine whether exogenous leptin reduces remote organ injury in the rats with thermal burn trauma. Leptin (10 microg/kg) or saline was administered intraperitoneally after burn injury, and the rats were decapitated at either 6 or 24 h. Plasma samples of 24-h burn group were assayed for the determination of monocyte and neutrophil apoptosis. Thermal injury increased tissue-associated myeloperoxidase (MPO) activity and microscopic damage scores in the lung, liver, stomach, colon and kidney of both 6- and 24-h burn groups. In the 6-h burn group, leptin reduced microscopic damage score in the liver and kidney only, while damage scores in the 24-h burn group were reduced in all the tissues except the lung. Also, in both burn groups, leptin reduced elevated MPO activity in all tissues except the lung. The percentage of mononuclear cells was significantly reduced at the 24 h of burn injury, while the granulocyte percentage was increased. Leptin treatment, however, had no significant effect on burn-induced reversal of white blood cell ratios. On the other hand, burn-induced increase in the death of mononuclear cells and granulocytes was significantly reduced in leptin-treated rats. The results of the present study suggest that leptin may provide a therapeutic benefit in diminishing burn-induced inflammation and associated multiple organ failure.

Estrogen Protects against Oxidative Multiorgan Damage in Rats with Chronic Renal Failure

The impact of sex dimorphism on chronic renal failure (CRF)-induced oxidative multiorgan damage and the effects of estradiol (E2) loss and E2 supplementation on the progress of CRF were studied. Sprague-Dawley rats underwent 5/6 nephrectomy (CRF), and a group of female rats had bilateral ovariectomy (OVX), while the sham-operated rats had no nephrectomy or OVX. Rats received either estradiol propionate (50 μg/kg/day) or vehicle for six weeks. Serum BUN levels were elevated in both male and female CRF groups treated with vehicle, while creatinine level was not significantly changed in the female CRF group. CRF-induced elevation in serum TNF-α of male rats was abolished when the animals were treated with E2, while OVX exaggerated TNF-α response. In OVX and male rats with CRF, E2 treatment reversed the malondialdehyde elevations in all the studied tissues (kidney, heart, lung, ileum, brain, liver, and gastrocnemius muscle), while depletion of glutathione in these tissues was prevented by E2 treatment. Similarly, increased levels of myeloperoxidase activity, lucigenin chemiluminescence, and collagen in most of the tissues were reversed by E2 treatment. The findings show that the extent of tissue injuries was relatively less in females, while ovariectomy exacerbated all the indices of oxidative injury. Moreover, the administration of E2, with its potent anti-oxidant and anti-inflammatory effects, markedly improved CRF-induced systemic inflammatory outcomes in both male and female rats by depressing tissue neutrophil infiltration and modulating the release of inflammatory cytokines.

Role of melatonin in reducing water avoidance stress‐induced degeneration of the gastrointestinal mucosa

Abstract:  We investigated the role of melatonin on water avoidance stress (WAS)‐induced degeneration of the gastric, ileal and colonic mucosa. Wistar albino rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing animals to acute (aWAS + mel group) or chronic WAS (cWAS + mel group), 10 mg/kg melatonin was injected i.p. The stomach, ileum and colon samples were investigated under light and scanning electron microscope. Malondialdehyde (MDA) and glutathione (GSH) levels were also determined. In both aWAS and cWAS groups, the epithelium of stomach showed ulceration in some areas, dilatations of the gastric glands and degeneration of gastric glandular cells; prominent congestion of the capillaries after WAS was apperent. In the cWAS group, severe vascular congestion was observed along with degeneration of ileal and colonic epithelium. MDA levels were increased and GSH levels were decreased in all tissues in both the aWAS and cWAS groups. The morphology of gastric, ileal and colonic mucosa in both aWAS + mel and cWAS + mel groups showed that the indole significantly reduced degeneration of the gastrointestinal mucosa. Decreased MDA and increased GSH levels were observed in the WAS + mel groups. Based on the results, melatonin treatment significantly prevented WAS induced degenerative morphological and biochemical changes of gastrointestinal mucosa.

Morphological alterations and distribution of occludin in rat testes after bilateral vasectomy

The aim of study was to investigate the fate and the morphology of the cells which constitute the spermatogenic line, and to determine the distribution of occludin in the testis in adult vasectomized Wistar rats. The rats were divided into two groups: control group (sham-operated) and vasectomized group. One, 3 and 6 months after sham and vasectomy operations, testis samples were examined. The weight of the testes was found to be reduced 3 and 6 months after vasectomy. There was vacuolization in the seminiferous tubules one month after vasectomy. The tubules showed severe atrophy 3 and 6 months after vasectomy. The occludin immunolabeling in the 3- and 6-month groups was weak and diffuse, and the density of the protein was found to be decreased. The increase in the number of apoptotic cells was accompanied by a time-dependent decrease in the number of haploid, diploid and tetraploid cells. This study demonstrated that vasectomy causes degeneration in the seminiferous tubules with alterations in occludin distribution with a decrease in the number of spermatogenic cells. Moreover, these alterations increase in a time-dependent manner.

Role of melatonin in reducing water avoidance stress-induced degeneration of the liver.

Melatonin, a pineal secretory product, is a potent scavenger of a variety of free radicals. We investigated the role of melatonin on water avoidance stress (WAS)–induced degenerations of the liver parenchyme. Wistar albino rats were exposed to acute WAS (aWAS group) or chronic WAS (cWAS group). Before exposing animals to acute (aWAS + mel group) or chronic WAS (cWAS + mel group), 10 mg/kg melatonin was injected i.p. The liver samples were investigated under light and transmission electron microscope. Malondialdehyde (MDA) and glutathione (GSH) levels were also determined. Prominent vascular congestion and dilated sinusoids, activated Kupffer cells with prominent morphology, dilated granular endoplasmic reticulum membranes, and focal picnotic nuclei were observed in the aWAS group; these morphological changes were severe in the cWAS group. MDA level was increased and GSH level was decreased significantly in the cWAS group. The morphology of liver parenchme in both the aWAS + mel and the cWAS + mel group showed that melatonin significantly reduced the degeneration in liver; besides, a significant decrease in MDA and an increase in GSH levels were observed in the cWAS + mel group. Based on the results, melatonin treatment significantly prevented WAS-induced morphological and biochemical changes in liver parenchyma.

Captopril protects against burn-induced cardiopulmonary injury in rats

BACKGROUND This study was designed to determine the possible protective effect of captopril treatment against oxidative damage in heart and lung tissues induced by burn injury. METHODS Under ether anesthesia, the shaved dorsum of Wistar albino rats was exposed to 90°C water bath for 10 seconds. Captopril was administered intraperitoneally (10 mg/kg) after the burn injury and repeated twice daily. In the sham group, the dorsum was dipped in a 25°C water bath for 10 seconds. At the end of the 24 hours, echocardiographic recordings were performed, then animals were decapitated and heart and lung tissue samples were taken for the determination of tumor necrosis factor-α (TNF-α) as a pro-inflammatory cytokine, malondialdehyde and glutathione levels and myeloperoxidase, caspase-3, and Na+,K+-ATPase activity in addition to the histological analysis. RESULTS Burn injury caused significant alterations in left ventricular function. In heart and lung tissues, TNF-α and malondialdehyde levels and myeloperoxidase and caspase-3 activities were found to be increased, while glutathione levels and Na+, K+-ATPase activity were decreased due to burn injury. Captopril treatment significantly elevated the reduced glutathione level and Na+, K+-ATPase activity, and decreased cytokine and malondialdehyde levels and myeloperoxidase and caspase-3 activities. CONCLUSION Captopril prevents burn-induced damage in heart and lung tissues and protects against oxidative organ damage.

Nesfatin-1 ameliorates sepsis-induced remote organ injury: The role of oxidant-antioxidant status and neutrophils

Purpose: Protective effects of nesfatin-1 was studied in sepsis-induced injury of remote organs. Methods: Male rats were randomly divided as control and sepsis (cecal ligationperforation) groups, treated with either saline or nesfatin-1 (10 μg/kg). At 16 h following surgery, samples of brain, kidney, liver and lung tissues were removed and myeloperoxidase (MPO) activity, glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured in these tissues. Results: In saline-treated septic rats, elevated MDA and MPO activities were accompanied with depleted CAT, SOD and GSH levels in the brain, kidney, liver and lung tissues, implicating extensive oxidative damage in all remote organs. Nesfatin-1 reduced MDA levels (brain, lung) and MPO activities (brain, kidney), and preserved antioxidant GSH (brain, lung), CAT (brain) and SOD (kidney) levels. Severe hepatocyte degeneration, neuronal damage, glomerulotubular degeneration and alveolar disturbance in saline-treated septic rats were replaced with regular tissue morphologies in nesfatin-1-treated rats. Conclusion: Nesfatin-1 alleviates oxidative damage by enhancing endogenous antioxidant systems and inhibiting recruitment of neutrophils, suggesting that nesfatin-1 may be have a potential therapeutic impact on the treatment of septic shock to reduce subsequent remote organ failure.