Brain activities of streptozotocin-induced diabetic Wistar rats treated with gliclazide: Behavioural, biochemical and histomorphology studies

Gliclazide (GLD), a sulphonylurea is efficacious in the treatment of diabetes type-2. However, there is limited information on its activity in the brain, especially in diabetics. This research investigated the brain activities of GLD following streptozotocin-induced diabetes in Wistar rats. Twenty five adult male Wistar rats (200-250 g) were grouped (n = 5) as: Control (distilled water, 5 mL/kg) and GLD (150 mg/kg) groups; and the diabetic groups, untreated streptozotocin (STZ, 35 mg/kg), and STZ (35 mg/kg) treated with GLD (150 mg/kg) for two and four weeks, and already on high fat diet. The animals' body weights and blood glucose levels were checked weekly. After the experimental duration, spontaneous alternation and novel object recognition tests were carried out and the animals sacrificed. Perfusion with phosphate buffered saline preceded brain excision for biochemical analyses, with halves fixed in 10% neutral buffered formalin for histology. Compared with the control, results showed (p < 0.05) declined spontaneous alternation and exploratory activities with no preference for familiar or novel objects, body weights loss, raised blood glucose, increased malondialdehyde with decreased superoxide dismutase concentrations, and no apparent adverse effect on hippocampal and prefrontal cortical Nissl substance in the untreated diabetic group. The adverse observations were attenuated in the GLD treated diabetic groups; although the spontaneous alternation in the four weeks GLD treated diabetic group improved (p < 0.05), exploration of objects increased (p < 0.05) without preference. The present results showed that treatment with GLD for two and four weeks mitigated STZ activities, even though there was less improvement in neurocognitive activities.