Mechanism Study On Benefical Effects Of Ginseng Total Saponin On Stress-induced Hippocampal Astrocyte Structure Plasticity Impairment In Mice

Stress is a reaction of the body to adapt to a changing adaptability to induce a series of changes in neuroendocrine system, the hippocampal tissue damaged and depression of clinical manifestations. The incidence rate of neuropsychiatric diseases induced by stress increased year by year and became a serious threat to human health. When exposed to strong and long-term physical and psychological stress stimuli, the patients have cognitive impairment and emotional disorders through hippocampal plasticity with hypothalamic-pituitary-adrenocortical (HPA) axis function hyperfunction and glucocorticoid levels rapidly increased. Quantitative and semi quantitative analysis of autopsy found bilateral hippocampal volume significantly reduced in major depressive disorder, but not a lot of nerve cell loss.Experimental study of apoptosis was further confirmed that apoptosis was only a very small amount of nerve cells. The number reduction of nerve cells was not the main factors of decrease in the size of the hippocampus.Objective:Long-term exposure to stress or high glucocorticoid levels produces significant reduction in hippocampal volume and induces depression-like behavior in rodent animals, the cause of which is not well known so far. Nevertheless, increasing evidence shows that astrocytes, the most abundant cells in the central nervous system, paly a very important role in supporting, nourishing, protecting and repairing neurons, explore the influence of chronic cortisone injection in mice hippocampal astrocyte.Methods:We investigated the effects of chronic corticosterone exposure on astrocytes in hippocampal tissues in male C57BL/6N mice. The number, somal volume and protrusion length of glial fibrillary acidic protein-positive astrocytes as well as hippocampal volume were assayed using imrnunocyto-chemistry and quantitative stereological techniques. To further assess astrocytes, we enzymatically analyzed glycogen levels in the hippocampus. Based on the stress pathogenesis and characteristics, the use of traditional Chinese medicine characteristic is a good method to solve this kind of problems on prevention of hippocampal damage, In order to determine the effectiveness and mechanism of Ginseng Total Saponin on prevention and treatment of chronic stress induced astrocytes injury, Ginseng Total Saponin was given in the molding process.Results:Chronic corticosterone injection induced depression-like behavior in male mice, decreased significantly the hippocampal volume and glycogen levels, as well as caused a decrease of astrocyte somal volume and protrusion length in the hippocampus. Interestingly, chronic corticosterone injections did not produce obvious effects on the number of astroctyes in the hippocampus. The results suggest that the reduction of hippocampal astrocyte structural plasticity might be a mechanism by which chronic corticosterone treatment causes hippocampal atrophy and depression-like behavior in male mice. Ginseng Total Saponin can exhibit protective effect on astrocytes, improve the model group depression behavior, down-regulate synaptic vesicle protein and increase brain glycogen and neurological nutrition factor, showed significant difference compared with the model group.Conclusion:Ginseng Total Saponin can play a protective role to hippocampal astrocytes by enhancing astrocyte repair function, against astrocyte injury induced by stress, reverse emotional and behavioral anomaly caused by astrocytes damage.