In this study, we investigated the protective effects of angiotensin IV (Ang IV) on cognitive function in streptozotocin (STZ)-induced diabetic rats. Male Wistar albino rats, were randomly divided into four groups; control (C), diabetes (Dia, 60 mg/kg, STZ, i.p.), Ang IV (5 µg/kg, s.c.) and Dia+Ang IV. The passive avoidance and Morris water maze (MWM) tests were used to evaluate learning and memory performance. Behavioral tests were carried out between 21 and 30 days after the initial Ang IV injection. Hippocampi were dissected and retained for biochemical and Western blot analysis. The Dia group exhibited the poorest behavioral results, while the Dia+Ang IV group performed highest on the MWM task. Superoxide dismutase, glutathione peroxidase, and malondialdehyde levels increased significantly in the Dia group compared to Dia+Ang IV. Brain-derived neurotrophic factor (BDNF) and N-methyl-D-aspartate levels were significantly elevated, while levels of GABAA significantly decreased, in the Dia+Ang IV group compared to the Dia group. These findings suggest that peripheral administration of Ang IV ameliorated spatial memory in diabetic rats by decreasing hippocampal oxidative stress and BDNF levels.

Our study aimed to determine the effects of losartan and PD123319 in ischemia–reperfusion (IR) injury in isolated perfused rat heart. The study used 40 male Wistar albino rats that were grouped as Control, IR, and IR treatment groups that received losartan (20 mg/kg), PD123319 (20 mg/kg), and losartan+PD123319. The hearts were attached to Langendorff isolated heart system by employing in situ cannulation method, and cardiodynamic parameters were recorded during the experiment. At the end of experiment, hearts were retained for biochemical analysis and all data were statistically evaluated. A partial recovery of cardiodynamic parameters was observed in all treatment groups. A significant increase in oxidative stress parameters were seen in the IR group, whereas all treatment groups exhibited lower increase. Furthermore, levels of all antioxidant parameters were significantly lower in the IR group, but higher in the treatment groups. Effects on all parameters were much more remarkable in the PD123319 group. Levels of angiotensin II and renin were increased (P < 0.001) with IR application and decreased (P < 0.001) with the treatment of both antagonists. In conclusion, treatment of losartan and PD123319 played a cardioprotective role against IR injury, PD123319 being more effective in this protection.

Objective: This study was designed for investigating the effectiveness of the Nigella sativa (N. sativa) extract on apoptosis in cerebrum and hippocampus and also plasma oxidative stress, in pentylenetetrazol (PTZ)-induced kindling rats. Materials and Methods:The kindling model was induced by subconvulsive doses (35 mg/kg i.p.) of intraperitoneal PTZ injections in N. sativa treated and non-treated PTZ groups (PTZ and PTZ + NS). The PTZ + NS group were also treated with an extract of N. sativa (10 mg/kg) 2 h before each PTZ injection. The total oxidant and antioxidant status, oxidative stress index, paraoxonase, arylesterase, catalase (CAT) and total thiol levels were analyzed in plasma. Brain derived neurotrophic factor (BDNF), cyclin-B1 and B-cell lymphoma 2 (Bcl-2) expressions were investigated in the cerebrum and hippocampus.Results: PTZ decreased the oxidative stress by increasing the activities of CAT, arylesterase, and paraoxonase. N. sativa decreased activities of arylesterase, paraoxonase, while increasing the CAT. It also brought the decreased BDNF and Bcl-2 expression levels to their normal levels in the cerebrum but not in the hippocampus. Conclusion:N. sativa treatment improved the PTZ induced-impairments in BDNF and Bcl-2 expressions, resulting in a neuronal apoptosis in the cerebrum, without affecting blood oxidative stress.

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