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

BACKGROUND: 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. MATERIAL AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.