Changes of Microglia in Hippocampus of Mice Induced by Maternal Separation with Restraint Stress and Regulatory Effect of Wenyang Jieyu Prescription / 中国实验方剂学杂志

ABSTRACT

Objective:To observe the activation of microglia in hippocampus of depressed and anxious mice induced by maternal separation with acute restraint stress and the expression of interleukin-1<italic>β</italic>（IL-1<italic>β</italic>），interleukin-6（IL-6），tumor necrosis factor-<italic>α</italic>（TNF-<italic>α</italic>）， investigating the mechanism of Wenyang Jieyu prescription in treating anxiety and depression. Method:Eighty four male C57BL offspring were randomly divided into control group， acute restraint stress group and model group on postnatal day 0（PD0）. Maternal separation combined with acute restraint stress was used to prepare anxious and depressed model mice， dividing the model mice into model group， Wenyang， Jieyu， Wenyang Jieyu and fluoxetine group according to random number table method. During the period of PD21-PD90， the control， acute restraint stress and model mice were fed with normal diet， with the other groups fed with corresponding medicine mixed diet. The Wenyang， Jieyu and Wenyang Jieyu groups were given 5.85， 12.03 and 16.71 g·kg^-1·d^-1 respectively. The fluoxetine group was given 2.60 mg·kg^-1·d^-1. Open field， zero maze test and social interaction tests were used to evaluate the anxiety and depression of model mice. The expression of Iba-1 in hippocampal microglia was detected by immunohistochemistry（IHC）. The mRNA expression of IL-1<italic>β</italic>， IL-6， TNF-<italic>α</italic>， Iba-1 and glucocorticoid receptor（GR）were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. Result:Compared with the control group， total movement distance and time spent in central zone in 5 min of the model mice significantly decreased（<italic>P</italic><0.01）， time spent in opened arm and total movement distance decreased significantly（<italic>P</italic><0.05，<italic>P</italic><0.01）， investigation time during testing and training increased significantly（<italic>P</italic><0.01）. The expression of Iba-1 protein and mRNA，IL-1<italic>β</italic>，IL-6，TNF-<italic>α</italic> mRNA significantly increased（<italic>P</italic><0.01）， the expression levels of GR mRNA significantly decreased（<italic>P</italic><0.01）. The result of IHC staining showed that microglia were over activated. Compared with the model group， total movement distance and time spent in central zone in 5 min of mice in the Wenyang Jieyu and fluoxetine group significantly increased（<italic>P</italic><0.05，<italic>P</italic><0.01）.Time spent in opened arm significantly increased（<italic>P</italic><0.01）. Investigation time during testing and training significantly decreased（<italic>P</italic><0.05，<italic>P</italic><0.01）. The expression of Iba-1 protein and mRNA，IL-1<italic>β</italic>，IL-6，TNF-<italic>α</italic> mRNA significantly decreased（<italic>P</italic><0.05，<italic>P</italic><0.01）. The expression of GR mRNA increased significantly（<italic>P</italic><0.05，<italic>P</italic><0.01）. IHC staining showed the microglia recovered. Time spent in opened arm of mice in the Wenyang group and Jieyu group significantly increased （<italic>P</italic><0.01）， time spent investigating during testing decreased significantly （<italic>P</italic><0.05）， the expression levels of Iba-1 protein and mRNA，IL-6 mRNA significantly decreased （<italic>P</italic><0.05，<italic>P</italic><0.01）. The expression of GR mRNA of mice in the Wenyang group significantly increased （<italic>P</italic><0.05）， the expression of TNF-<italic>α </italic>mRNA significantly decreased （<italic>P</italic><0.05）. Total movement distance of mice in the Jieyu group increased significantly （<italic>P</italic><0.01）， time spent investigating during training decreased significantly （<italic>P</italic><0.05），the expression level of IL-1<italic>β </italic>mRNA significantly decreased （<italic>P</italic><0.05）. IHC staining showed that microglia recovered partly in both groups. Conclusion:The comprehensive curative effect and pharmacological action of Wenyang Jieyu prescription were better than Wenyang prescription and Jieyu prescription. Wenyang Jieyu prescription can treat anxiety and depression in maternal separation and acute restraint stress mice， its possible mechanism may be related to the decreased activation of microglia， down-regulation of IL-1<italic>β</italic>，IL-6，TNF-<italic>α</italic> expression and up-regulation of GR expression.