Protective effect of melatonin on renal injury of rats induced by bile duct ligation

Protection against experimental cisplatin-induced optic nerve toxicity using resveratrol: A rat model study

AIM

To investigate the effects of resveratrol on oxidative stress and inflammation parameters and histological alterations in cisplatin-induced optic nerve damage in a mouse model.

MATERIAL AND METHOD

Thirty-six albino Wistar male rats were divided into three groups as control, 5 mg/kg cisplatin-administered (Cis) and 5 mg/kg cisplatin + 25 mg/kg resveratrol-administered (Cis + Res) animals. At the end of the experimental period, the rats were sacrificed with high-dose (50 mg/kg) thiopental sodium, and their optic nerves were dissected. Malondialdehyde (MDA), total glutathione (tGSH), total oxidant status (TOS), total antioxidant status (TAS), tumour necrosis factor alpha (TNF-α), nuclear factor kappa B (NF-KB) levels, and histopathological findings were assessed using the optic nerve tissues.

RESULTS

In the Cis + Res group, the MDA, TOS, OSI, TNF-a and NFK-B levels were significantly lower and the tGSH and TAS levels were significantly higher compared with the Cis group (P = 0.001). In histological evaluations, there were dilated and congested blood vessels, destruction, oedema, degeneration, haemorrhage, and proliferating capillaries indicating the presence of inflammation and damage only in the Cis-administered group. However, in the Cis + Res group, the histological findings were very similar to the healthy controls.

CONCLUSION

Resveratrol is a promising neuroprotective agent for cisplatin-induced optic nerve toxicity with its anti-oxidant and anti-inflammatory effects. Further investigations are needed to evaluate the possible therapeutic effects on other optic nerve toxicities.

An experimental study of exenatide effects on renal injury in diabetic rats1

PURPOSE

To investigate the effects of exenatide on renal injury in streptozotocin-induced diabetic rats.

METHODS

Fifty SD rats were randomly divided into normal control, model, exenatide-1, exenatide-2 and exenatide-3 groups, 10 rats in each group. The diabetic nephropathy model was constructed in later 4 groups. Then, the later 3 groups were treated with 2, 4 and 8 μg/kg exenatide for 8 weeks, respectively. The serum and urine biochemical indexes and oxidative stress and inflammatory indexes in renal tissue were determined.

RESULTS

Compared to the model group, in exenatide-3 group the serum fasting plasma glucose and hemoglobin A1c levels were significantly decreased, the fasting insulin level was significantly increased, the renal index and blood urea nitrogen, serum creatinine and 24 h urine protein levels were significantly decreased, the renal tissue superoxide dismutase and glutathione peroxidase levels were significantly increased, the malondialdehyde level was significantly decreased, and the renal tissue tumor necrosis factor alpha, interleukin 6, hypersensitive C-reactive protein and chemokine (C-C motif) ligand 5 levels were significantly decreased P<0.05).

CONCLUSIONS

Exenatide can mitigate the renal injury in diabetic rats. The mechanisms may be related to its resistance of oxidative stress and inflammatory response in renal tissue.

Preventing oxygen free radical damage by proanthocyanidin in obstructive jaundice

OBJECTIVE

Tissue damage and endotoxemia in obstructive jaundice are attributed to the increase in oxygen free-radicals. We aimed at evaluating the possible protective effect of grape seed proanthocyanidin extract (GSPE), which is a potent exogenous free-radical scavenger and antioxidant.

MATERIAL AND METHODS

The study was performed at the Necmettin Erbakan University Meram School of Medicine Research and Application Center for Experimental Medicine Laboratory with ethical approval. 30 Wistar-Albino rats were used and were divided into 3 groups. The common bile duct was identified and only dissected in the first group (sham). Following dissection of the common bile duct it was ligated with 4/0 silk just above the pancreas in the second group (control). After ligation of the common bile duct, 100mg/kg/day GSPE was administered via orogastric lavage for 10 days in the third group.

RESULTS

Biochemical values revealed a statistically significant difference between Group I and the others. There was no difference between Group II and III regarding biochemical values. There was a statistically significant difference, however, between Group II and III with regards to nitric oxide levels. There was a statistically significant difference between Group I and the other groups concerning hepatic and pulmonary tissue damage on histopathologic evaluation. There was no difference among the groups with regards to renal tubular damage.

CONCLUSION

Proanthocyanidin is an effective natural antioxidant in decreasing the level of tissue damage caused by oxygen free-radicals.

Melatonin protects against taurolithocholic-induced oxidative stress in rat liver

Cholestasis, encountered in a variety of clinical disorders, is characterized by intracellular accumulation of toxic bile acids in the liver. Furthermore, oxidative stress plays an important role in the pathogenesis of bile acids. Taurolithocholic acid (TLC) was revealed in previous studies as the most pro-oxidative bile acid. Melatonin, a well-known antioxidant, is a safe and widely used therapeutic agent. Herein, we investigated the hepatoprotective role of melatonin on lipid and protein oxidation induced by TLC alone and in combination with FeCl(3) and ascorbic acid in rat liver homogenates and hepatic membranes. The lipid peroxidation products, malondialdehyde and 4-hydroxyalkenals (MDA + 4-HDA), and carbonyl levels were quantified as indices of oxidative damage to hepatic lipids and proteins, respectively. In the current study, the rise in MDA + 4-HDA levels induced by TLC was inhibited by melatonin in a concentration-dependent manner in both liver homogenates and in hepatic membranes. Melatonin also had protective effects against structural damage to proteins induced by TLC in membranes. These results suggest that the indoleamine melatonin may potentially act as a protective agent in the therapy of those diseases that involve bile acid toxicity.

The Effect of Melatonin on Plasma Oxidant-Antioxidant Skeletal Muscle Reperfusion Injury in Rats

We investigated the effects of melatonin administration on skeletal muscle ischaemia-reperfusion injury (IRI) by assessing plasma malondialdehyde (MDA), superoxide dismutase (SOD), total glutathione (GSSH), glutathione peroxidase (GPX) and myeloperoxidase (MPO) concentrations. Male Sprague-Dawley rats ( n = 32) were randomized into four groups: group 1 served as time controls; group 2 were the test animals; group 3 received melatonin (30 mg/kg) intraperitoneally prior to the induction of ischaemia; and group 4 received melatonin (30 mg/kg) intraperitoneally prior to the reperfusion period. Administration of melatonin prior to reperfusion significantly decreased the elevated MDA concentration caused by IRI, and significantly elevated GSSH concentrations, which had been reduced by IRI. Ischaemia-reperfusion injury significantly increased activities of GPX, SOD and MPO, and melatonin administration reversed this effect. In conclusion, a pharmacological dose of melatonin showed significant protective effects against IRI by decreasing lipid peroxidation, MPO, SOD and GPX enzyme activities and regulating glutathione content.