Decreased expression of mucin-1 in endometriosis endometrium correlated with progesterone receptor B involved in infertility.

Abstract

Mucin-1(MUC1), a type of glucoprotein, has various expression statuses on the endometrium at different menstrual phases. Normal expression of MCU1 is closely related to successful blastocyst implantation. MUC1 was synthesized and secreted by the glandular epithelium of the endometrium, which acts as a barrier to foreign bodies. The endometrium was able to recognize and accept the blastocyst implantation. Endometriosis has lower rates of successful implantation with in vitro fertilization and embryo transfer, which may involve the altered expression of MUC1 on eutopic endometrium. In vitro studies demonstrated that progesterone and its receptors affected MUC1 expression under different physiopathology conditions. Our study was designed to explore whether progesterone receptors alteration contributed to MUC1 varied expression on endometriosis endometrium. A total of 54 patients with different infertility reason were selected retrospectively from the First Affiliated Hospital of Soochow University and Kowloon Hospital, Suzhou, China. Endometrium samples were collected under operative procedures. The samples were assigned to two groups: endometriosis (n = 28) and oviduct block (control group, n = 26), on which we examined the expression of progesterone receptor B (PR-B) and MUC1, respectively, using immunohistochemistry and Western blotting. Compared with the control group, the expression of MUC1 was significantly decreased in the mid-secretory phase of the menstrual cycle in endometriosis. There was relatively lower expression of MUC1 in different phases of the cycle in comparison with the control group. The varied expression of MUC1 was significantly related to PR-B variation in endometriosis endometrium (r = 0.763, P < 0.01). Decreased expression of MUC1 may attribute to PR-B variation in the mid-secretory phase of endometriosis endometrium. It might be one of the factors resulted in infertility in endometriosis patients.