Triphasic expression of interleukin-1 receptor type I in human endometrium throughout the menstrual cycle of fertile women and women with unexplained infertility

Abstract

Objective: To evaluate expression of interleukin-1 receptor type I in the endometrium of fertile women throughout the menstrual cycle and to investigate whether unexplained infertility may be associated with abnormal expression of IL-1 receptor type I. Design: Retrospective study using immunohistochemical technique, Western blot assay, and reverse transcription polymerase chain reaction. Setting: Gynecology clinic and human reproduction research laboratory. Patient(s): 39 fertile women and 25 women with unexplained infertility. Intervention(s): Endometrial biopsy of samples obtained at laparoscopy. Main Outcome Measure(s): Immunostaining intensity, molecular weight, and messenger RNA levels of IL-1 receptor type I. Result(s): Immunostaining showed that two threshold days (13 and 22) separate the menstrual cycle into three distinct periods of IL-1 receptor type I expression, both in epithelial and stromal cells. Results of Western blot assay and reverse transcription polymerase chain reaction confirmed the immunohistochemical data. Statistical analyses showed that the pattern of IL-1 receptor type I expression was similar in women with unexplained infertility and fertile women. Conclusion(s): IL-1 receptor type I exhibits three distinct levels of expression throughout the menstrual cycle in the endometrium of fertile women, suggesting different physiologic roles of the receptor within the cycle. However, IL-1 receptor type I does not seem to be involved in unexplained infertility.