Curcumin mitigates stress induced depression and hippocampal damage through upregulation of BDNF expression and adult neurogenesis.

Abstract

Chronic stress, recognized as a major precipitant of depression, has been linked to various neural alterations, including cell death, neuronal atrophy, and compromised hippocampal neurogenesis and plasticity. This study aim to scrutinize curcumin's influence on glucocorticoid hormone secretion and its subsequent effects on the structural integrity and neurogenesis of the hippocampal neurons. A total of 30 adult albino Wistar rats, each weighing between 200-250 g, were utilized for the study. The rats, excluding those in the control group, underwent a 42-day regimen of modified Chronic Unpredictable Stress (CUS) to induce depressive-like states. After inducing CUS, these rats were categorized into six groups, each receiving different oral treatments for two weeks. The treatments included 30 mg/kg body weight of curcumin, 20 mg/kg body weight of fluoxetine, or a combination of both, along with a control group that received distilled water and an olive oil treated group. The rats were tested for behavioural despair using the forced swim test and their blood samples were obtained for serum corticosterone test. Afterwards, the rats were anesthetized, transcardially perfused and the hippocampus dissected and prepared for histopathological study. The study's multi-faceted approach encompassed behavioral, biochemical, and histological evaluations. Behavioral despair, gauged through the forced swimming test, displayed a marked reduction in the curcumin-treated rats compared to controls (p<0.05). Additionally, curcumin significantly lowered serum corticosterone levels, aligning them closely with the control levels. Histomorphological analysis of the hippocampus showed that the curcumin- treated rats exhibited substantially less neurodegeneration, as evidenced by fewer cytoplasmic vacuolations and more intact neuronal structures. Increased cell proliferation and BDNF level were also observed in curcumin treated rats. This study has illuminated a multifaceted approach through which curcumin mitigates hippocampal neurodegeneration, thus showing possible therapeutic potential of curcumin in ameliorating depressive symptoms.