Effects of notoginsenoside R1 on attenuating depressive behavior induced by chronic stress in rats through induction of PI3K/AKT/NF‐κB pathway

Abstract Chronic unpredictable mild stress (CUMS) can cause a series of depressive symptoms in depression patients. Recently, notoginsenoside R1 (NGR1) has been reported to play crucial roles in the anti‐inflammatory, antioxidant, and anti‐apoptotic. However, the role and mechanisms of NGR1 in improving symptoms of depressive behavior remain unknown. Evaluating and identifying its value and exploring the mechanisms of NGR1 on CUMS‐induced depressive behavior were the aims of this study. Here, rats were separated into five different groups and treated with or without different concentrations of the NGR1. Then, the body weight, sucrose preference rate, immobility time, crossing number, rearing number, and grooming number were determined to evaluate the effect of NGR1 on improving the depressive behavior of CUMS rats. Subsequently, the morphology of hippocampal neurons and protein expression of brain‐derived neurotrophic factor in each group were examined by hematoxylin and eosin staining and western blot to show the neuroprotective effects of NGR1. Furthermore, the mRNA and protein expression of TNF‐α, IL‐6, and IL‐1β were also detected by quantitative polymerase chain reaction (qPCR) and enzyme‐linked immunosorbent assay to verify the anti‐inflammatory effects of NGR1 on CUMS rats. In addition, the cell apoptosis‐related proteins were examined to reveal that NGR1 can inhibit cell apoptosis in CUMS rats. Moreover, it was confirmed that NGR1 attenuated the symptoms of depressive behavior by mediated PI3K/Akt/NF‐κB pathway. Together, this study shows that NGR1 improves depressive behavior induced by chronic stress in rats through activation of PI3K/AKT/NF‐κB pathway.