Protective effect of Hypericum perforatum on dexamethasone-induced diabetic depression in rats

Background/aim Complex interactions among psychological, social, and biological factors are the reason for diabetic depression. The present study was designed to evaluate the effect of Hypericum perforatum extract on dexamethasone-induced diabetic depression. Materials and methods A total of 24 adult male Wistar rats were divided into four groups (six rats each): group 1: control; group 2: daily treated with dexamethasone (0.44 mg/kg; intraperitoneally for 28 days); and groups 3 and 4: daily treated with H. perforatum extract (100 and 200 mg/kg; orally) concurrent with dexamethasone injection for 15 consecutive days. Plasma levels of blood glucose, glucose transporter-2, CD4, total antioxidant capacity, malondialdehyde, and nitric oxide were measured. In addition, the brain contents of serotonin, dopamine, cyclooxygenase-2, and transforming growth factor-β1 were determined. Moreover, assessment of histopathological changes of brain tissues and immunohistochemical analysis of caspase-9 were performed. Results Significant elevations were recorded in blood glucose level and plasma levels of malondialdehyde and nitric oxide. In addition, brain contents of dopamine, transforming growth factor-β1, and cyclooxygenase-2 were increased significantly in dexamethasone-treated group. However, plasma levels of glucose transporter-2, CD4, and total antioxidant capacity and the brain content of serotonin were significantly decreased in comparison with control group. Both doses of H. perforatum significantly ameliorated all biochemical parameters and alleviated histopathological and immunohistochemical apoptotic changes induced by dexamethasone in the rat cortex, striatum, and hippocampus. Conclusion H. perforatum extract possesses antioxidant, anti-inflammatory, and immunomodulatory effects against dexamethasone-induced diabetic depression.