Testosterone reduces tight junction complexity and down-regulates expression of claudin-4 and occludin in the endometrium in ovariectomized, sex-steroid replacement rats

Abstract

Background/Aim: It was hypothesized that endometrial tight junction morphology and expression of tight junction proteins i.e., claudin-4 and occludin in the uterus, are affected by testosterone. Therefore, the effects of testosterone on these parameters in the uterus during receptivity period were investigated. Materials and Methods: Ovariectomized adult female rats were given testosterone (1 mg/kg/day) alone or in combination with flutamide or finasteride between days 6 to 8 of sex-steroid replacement treatment, which was considered the period of uterine receptivity. Ultramorphology of tight junctions was visualized by transmission electron microscopy while distribution and expression of claudin-4 and occludin were examined by immunofluorescence and real-time polymerase chain reaction respectively. Results: Administration of testosterone caused loss of tight junction complexity and down-regulated expression of claudin-4 and occludin in the uterus. Conclusion: Decreased endometrial tight junction complexity and expression of claudin-4 and occludin in the uterus during receptivity period by testosterone may interfere with embryo attachment and subsequent implantation.