Solanum aethiopicum Leaves Extract Attenuates Brain Dysfunction in Chronic Mild Stress Depressed Rats

Abstract

Depression is a mental health condition arising from neurochemical alterations that can result from chronic stress. Its management is complex, requiring targeted pathways for intervention, however, the role of antioxidants is essential. Solanum aethiopicum (SA) is one of such antioxidant sources that may abate stress. This study, therefore, investigated the effect of SA leaves ethanol extract on the hippocampus and cerebellum in rats following chronic mild stress (CMS). Twenty-five male adult Wistar rats weighing 180-250g were assigned into five groups (n=5): Control (10mL/kg distilled water); CMS group (CMS-only for 28 days), CMS-SA200 and CMS-SA400 [CMS and SA leaf extract (at 200 and 400mg/kg respectively, from day 15-28)] and 400 mg/kg SA group for 14 days. All the treatments were oral, and the rats were tested for sucrose preference, learning and anxiety, and subsequently sacrificed. Serum superoxide dismutase (SOD) and malondialdehyde (MDA) were analysed, and the hippocampus and cerebellum were processed for haematoxylin and eosin staining. Results showed significantly (p<0.05) decreased sucrose preference, spontaneous alternation, open arm entry/duration and SOD, as well as increased (p<0.05) MDA and slightly enlarged hippocampal pyramidal and cerebellar Purkinje cells nuclei in the CMS-only group. Treatment with SA in the CMS-SA200, CMS-SA400 and SA400 groups significantly (p<0.05) reversed the anhedonia, spontaneous alternation and anxiety-like activities, while there was no significant (p<0.05) change to SOD and MDA levels compared with the CMS-only group. However, the enlarged hippocampal and cerebellar cells nuclei persisted, which may be physiological. In conclusion, SA reversed chronic mild-stressed-impaired cognition, anhedonia, and anxiety-like effects, whose action was better at the higher dose