Altered micro-ribonucleic acid expression profiles of extracellular microvesicles in the seminal plasma of patients with oligoasthenozoospermia

Abstract

Objective: To determine whether microRNA (miRNA) expression profile is different in extracellular microvesicles collected from seminal plasma of men with oligoasthenozoospermia, to gain further insight into molecular mechanisms underlying male infertility.

Design: Microarray with quantitative real-time polymerase chain reaction validation and Western blot analysis confirmation.

Setting: University research and clinical institutes.

Patient(s): A total of 24 men, including 12 oligoasthenozoospermic subfertile men and 12 normozoospermic men.

Intervention(s): None.

Main outcome measure(s): Statistically significant altered miRNA expression profiles in oligoasthenozoospermic subfertile men compared with normozoospermic fertile men.

Result(s): Extracellular microvesicles including exosomes were isolated from seminal plasma by ultracentrifugation. Presence of exosome-specific proteins was confirmed by Western blotting. In the extracellular microvesicles, we analyzed 1,205 miRNAs by microarray and identified 36 miRNAs with altered expression levels in oligoasthenozoospermic compared with normozoospermic fertile men. Seven miRNAs were overexpressed and 29 miRNAs were underexpressed in oligoasthenozoospermic men. Using quantitative real-time polymerase chain reaction as an independent method, we confirmed the significantly higher expression levels of miR-765 and miR-1275 and the significantly lower expression level of miR-15a in oligoasthenozoospermic subfertile men as compared with the normozoospermic men.

Conclusion(s): We identified altered expression levels of miRNAs in extracellular microvesicles from seminal plasma as part of the molecular events in the male genital tract. These miRNAs may help to understand the molecular mechanisms underlying male infertility.

Keywords: Exosomes; male infertility; microRNA; seminal plasma; spermatogenesis.