Distribution of S100 protein in uterus of rats during the estrus cycle

【Objective】 The trail was conducted to study the expression of S100 protein in uterus of the rats during estrus cycle.【Method】 Sixteen mature female SD rats were divided randomly into 4 groups:preoestrus,estrum,metoestrus and diestrus,by vaginal smear,the expression of S100 protein in uterus of the rats during estrus cycle was studied by immunohistochemical SP method.【Result】 The expression and variation of S100 protein exist in uterus in rat estrous cycle.The immunoreactive products are mainly located in endometrial epithelial cells,epithelial cells,stromal cells,endothelial cells,vascular smooth muscle cells,mast cells,smooth muscle cells and fibroblasts.There is no much difference in the expression regulation of S100 protein immunoreactive products in muscular and the endometrium in different periods,but there are some similar rules to follow:the expression of S100 protein in proestrus is slight,then it is strongly expressed in estrus,while it decreases in metoestrus.At last,the expression of S100 is re-increased in metestrus.They present the bimodal distribution.【Conclusion】The results show that the expression of S100 protein in the uterus follows some certain rules and might be mediated by the sex steroid hormone.