Effect of traditional Chinese herbal Bu‐Wang‐San on synaptic plasticity in ovariectomised rats

Objectives The neuroprotective effects of Bu-Wang-San (BWS) and its effects on spine synapse plasticity were investigated in ovariectomised rats. Methods Thirty-six ovariectomised rats were divided into three groups: untreated controls, treatment with 17β-estradiol or with BWS. After 3 months, spatial acquisition and spatial retention were measured using the Morris water maze. Swim time, swim distance, swim speed, quadrant time and platform crossing were recorded. Spine synapse density in the hippocampus was examined by transmission electron microscopy. The expression of synaptophysin P38 (P38) mRNA was examined by real-time PCR and the protein expression of P38 was examined by Western blot. Key findings In spatial acquisition and spatial retention, the BWS group functioned significantly better than the control group. Ultrastructural observation of the hippocampus showed that BWS significantly increased spine synapse density compared with the ovariectomised group. In addition, BWS significantly increased P38 mRNA and protein expression in the hippocampus. Thus, the positive effect of BWS on learning and memory in rats was associated with increased spinal synapse density and increased P38 mRNA and protein expression in the hippocampus following menopause-induced injury. Conclusions These results suggest that BWS could improve cognitive ability following menopause-induced impairment of learning and memory.