Collagen types in relation to expression of estradiol and progesterone receptors in equine endometrial fibrosis

Abstract

The aim of this study was to determine the influence of collagen I and III on the expression of estrogen and progesterone receptors in equine endometrial fibrosis. A total of 25 crossbred mares were studies. Two endometrial samples were collected from each mare,1 inthe estrus and1 inthe diestrus phase. The samples were classified according to histological changes. Collagen was typed and quantified using the picrosirius red histochemical technique, and steroid receptors were identified by immunohistochemistry. The results showed a predominance of collagen type III in all the endometrial samples. The expression of estrogen (RE2) and progesterone (RP4) receptors varied according to the estrous cycle. RE2 and RP4 expression varied in the estrus and diestrus phases; there was no influence of collagen I or II on receptor expression.