Sperm DNA fragmentation and apoptosis in the sperm of men with oligozoospermia are closely related to anti-ODF2 autoantibodies.

Abstract

Around 15% of couples of childbearing age suffer from infertility; in 50% of these cases, the male factor is present. In this study, we investigated the association between anti-ODF2 autoantibody existence and the DNA fragmentation and apoptosis of sperm in oligozoospermia men. 35 fertile men and 57 oligozoospermia men are enrolled in this study as control and case groups, respectively. After the identification of ODF2 as a possible target of anti-sperm antibodies in sera of oligozoospermia men using two-dimensional gel electrophoresis followed by western blotting and mass spectrometry, the case group serums were screened for anti-ODF2 autoantibodies and divided into anti-ODF2 negative (N=24) and positive (N=33) subgroups to follow assays. The mRNA expression levels of ODF2, Caspases 3, 8, 9, BAX, and BCL-2 were evaluated via qRT-PCR in spermatozoa samples of mentioned groups. DNA fragmentation and apoptosis rate of spermatozoa in studied groups were assessed using an SDF kit and flow cytometry, respectively. Mass spectrometry showed that ODF2 is one of the anti-sperm antibodies targeted in oligozoospermia patients. 33 of 57 oligozoospermia men had anti-ODF2 autoantibody in their sera. An elevated expression of ODF2 mRNA was observed in spermatozoa of anti-ODF2+ patients compared to anti-ODF2- patients and controls. There was an increased expression level of Caspase 3, 8, 9, and BAX and decreased expression of BCL-2 in spermatozoa of anti-ODF2+ patients compared to anti-ODF2- patients and controls. Noticeable increases in DNA fragmentation and apoptosis rate of anti-ODF2+ patients' spermatozoa were observed compared to anti-ODF2- patients and healthy controls spermatozoa. A positive correlation was observed between ODF-2 expression and DNF fragmentation and apoptosis rate of anti-ODF2+ patients' spermatozoa. Our results revealed that ODF2 is one of the main spermatozoa structural proteins, which is one of the anti-sperm antibodies targets, and its dysregulated expression may result in an increased rate of sperm DNA fragmentation and apoptosis.