Effect of Baihe Dihuang Decoction on synaptic plasticity of hippocampus in rats with anxious depression

Abstract

To explore the effect of Baihe Dihuang Decoction on the synaptic plasticity of hippocampal neurons in rats with anxious depression. Fifty SD rats were randomly divided into normal group, model group, venlafaxine group(6.75 mg·kg~(-1)), high-dose Baihe Dihuang Decoction group(8.64 g·kg~(-1)) and low-dose Baihe Dihuang Decoction group(4.32 g·kg~(-1)). Chronic restraint stress(6 h) combined with corticosterone(ih, 30 mg·kg~(-1)) was used to establish an anxious depression model, and 7 days after modeling, the administration started and continued for 21 days. The anxiety and depression-like behaviors of the rats were evaluated. Golgi-Cox staining and electron microscopy were used to observe the morphology and ultrastructural changes of synaptic dendrites. Immunofluorescence was used to detect the expression of hippocampal synaptic plasticity protein synapsin-1 and postsynaptic density protein 95(PSD-95). Western blot method was used to detect the expression of functional protein synaptophysin(SYP) and synaptic Ras GTPase activating protein(SynGap). The results showed that the rats in the model group had obvious anxiety and depression-like behaviors, the hip-pocampal dendritic spine density and branch length were reduced, the number of synapses was cut, and the internal structure was da-maged. The average fluorescence intensity of synapsin-1 and PSD-95 was significantly reduced and the expression of SYP and SynGap also decreased. High-dose Baihe Dihuang Decoction could significantly improve the anxiety and depression-like behaviors of model rats, relieve synaptic damage, and increase the expression of synapsin-1, PSD-95, SYP, and SynGap proteins. Therefore, we believe that Baihe Dihuang Decoction can improve anxiety and depression behaviors by regulating the synaptic plasticity of hippocampal neurons.