Role of genetic variations and protein expression of β-Microsemino protein in intrauterine insemination outcome of unexplained infertile men: A case-control study.

Background: Intrauterine insemination (IUI) is often the first-line treatment for unexplained infertility. $\beta$ -Microsemino protein (MSMB) is an abundant protein in seminal plasma that has an inhibitory effect on spontaneous acrosome reaction.

Objective: The present study aimed to evaluate MSMB gene variations and protein expression on IUI success rate in unexplained infertile men.

Materials and methods: A case-control study was performed on 100 unexplained infertile Iranian men referred to the Royan Institute, Tehran, Iran for IUI (50 men with IUI positive result [IUI+], and 50 men with IUI negative result [IUI-]). Couples with female infertility factors (such as hormonal disorders, infrequent menstrual period, abnormality in uterus, fallopian tubes, or ovaries) and men with infections of the male accessory glands, hypogonadotropic hypogonadism, clinical varicocele, retractile testis, genital trauma, drug use, or concurrent hormonal treatment Y chromosome microdeletions, and abnormal karyotype were excluded from the study. The polymerase chain reaction sequencing was performed for the promoter and the coding regions of MSMB functional domains. To study the protein expression, the total protein of sperm was extracted, and sandwich enzyme-linked immunosorbent assay was performed.

Results: 4 variations were detected (rs12770171, rs10993994, rs2075894, and rs4517463). None of them showed significant differences between the IUI+ and IUI- groups. The mean value of protein expression did not show any differences between the groups.

Conclusion: In conclusion, there is no association between genetic variations of promoter and coding regions of MSMB functional domains as well as its expression with IUI success in unexplained infertile men.