Changes Of Central Astrocytes In Maternal Separation Mice And The Regulation Of Wenyang Jieyu Decoction On It

ObjectivesEarly life stress,such as childhood trauma,maternal deprivation,abuse in early life,etc.,can increase the susceptibility of mental and behavior disorders.With the continuous research on the function of astrocyte(As),it has been found that it plays an important role in the pathogenesis of mental disorders,and become a new focus in the study of the pathophysiological mechanism of depression.Maternal separation animal model is an important tool to study the pathophysiological mechanism of depressive disorder caused by early life stress.Our previous researches have shown that Wenyang Jieyu Formula(XSF)has remarkable regulatory effect on mice's abnormal behaviors,HP A hyperfunction,neurotransmitter changes,and neuroplasticity reduction caused by maternal separation.Therefore,to explore the effect of maternal separation at different developmental stages on brain astrocytes,and XSF effect on the changes of brain astrocytes at infant development stage and adult stage,can provide the evidence for early prevention and treatment to diseases related to early adverse experience.Materials and Method1.The day of born as PDO,mice who were suffered 8 h/d maternal separation at PD5-PD14,were made as animal model(MS).At 10 days after maternal separation(PD 15),after weaning(PD24),40 days of age(PD40),2 months of age(PD60),3 months of age(PD90),the brains were fixed by perfusion and consecutive pathological sections were performed.Immunohistochemistry was used to label astrocytes with glial fibrillary acidic protein(GFAP),and compare to normal mice,the morphological changes and the number of astrocytes in the hippocampus of MS mice were observed.2.The mice who had been suffered postnatal maternal separation,were randomly divided into maternal separation group(MS),Wenyang group(Wenyang),Jieyu group(Xiaoyao),Wenyang Jieyu group(XSF)and Fluoxetine group(FLU).Different treatment method which used different Chinese medicine such as 2.52 g/kg Erxian decoctio for Wenyang,3.85 g/kg Xiaoyao San for Xiaoyao,5.25g/kg WenyangJieyu Formula for XSF,and 20mg/kg fluoxetine for FLU,performed at weaned(PD21)to adult(PD90)and adult respectively in different trial.The behavioral pattern was determined through the open field and free activity experiment,the O maze,and social interactiontest,GFAP expression was detected to observe changes of brain astrocytes.ResultsAstrocyte changes in developmental MS miceImmunohistochemical results display,in the PD 15-PD90 periods,the expression of GFAP in the hippocampus of MS mice increased.In the hippocampal region,the value of GFAP IOD in MS werelower than that in NC at different periods before PD60,and there was significantly difference at PD 15(P<0.05).At PD90,the value of GFAP IOD in MS was significantly higher than that of NC in CA3 area(P<0.01),and just higher in DG area,but there is no statistical difference.Effects of three formula of Wenyang and/or Xiaoyao on behavioral Patterns and astrocyte in MS Mice during development periodIn the open field and free activity experiment,the 30-minute total distance moved of MS mice increased compared with NC,and the difference was statistically significant(P<0.05).XSF had a decreasing trend compared with MS,but the difference was not statistically significant(P=0.096).The time of training exploration and identification exploration were prolonged in the social interaction behavior experiment of MS mice(P<0.05,P<0.05).There was a down-regulation in each drug group(P<0.05,or P<0.01).Immunohistochemical results display,in the hippocampal CA1 and DG area,the GFAP IOD value of MS mice was lower than that of NC(P<0.05,P<0.05).In the hippocampal CA3 area,the GFAP IOD value of MS mice was lower than NC,but the difference was not statistically significant(P=0.072).Except for Wenyang in the CA1 area,the IOD value of GFAP had an upward trend compared with MS,but the difference was not statistically significant(P=0.055),the rest of the drug administration groups were significantly upregulated compared with MS(P<0.05).Effects of three formula of Warm Yang and/or sooth qi on behavioral Patterns and astrocyte in MS Mice during adult periodIn the adult period treatment experiment,the 30-minute total distance moved of the free activity experiment of XSF had a decreasing trend compared with MS,but there was no statistical difference(P=0.081).In the social interaction test,time of training exploration and identification exploration of Xiaoyao and FLU were significantly down-regulated compared with MS(P<0.05).Compared with MS,three treatment formula had no effect on GFAP expression in hippocampal CA1 region,the expression of Wenyang GFAP was up-regulated in CA3 and DG regions(P=0.090,P=0.089),and the expression of Xiaoyao GFAP was up-regulated in DG region(P=0.097),but the difference was not statistically significant.XSF showed remarkable up-regulated changes in CA3 and DG area(P<0.01,P<0.05).Conclusion1.The number of central astrocytes rapidly increases from 2 to 3 weeks after birth and then slowly changes to adulthood.Maternal separation can reduce the number of astrocytes in the hippocampal regions of early developing mice,which approach normal after PD60.2.Erxian Decoction and Xiaoyao San can improve the social cognitive function of MS mice,and Wenyang Jieyu Decoction can regulate the anxiety level and social cognitive function of MS mice simultaneously.All three foumula(Erxian Decoction,Xiaoyao San,and Wenyang Jieyu Decoction)had a significant regulatory effect on astrocytes in hippocampus,hint that astrocytes may be a common way of different mechanism.3.From the results of treatment effect of Erxian Decoction,Xiaoyao San,and Wenyang Jieyu Formula,Wenyang Jieyu Formula coincided with the syndrome of maternal separation mice.The treatment effects in developmental period were better than that in adult period,suggested that early adverse experiences should be intervened the earlier for the better outcom.