[Relationship of abnormal sperm DNA methylation with early spontaneous abortion].

ABSTRACT

OBJECTIVE: To investigate the relationship between the abnormal sperm DNA methylation level and early spontaneous abortion. METHODS: We randomly selected 98 males who met the inclusion criteria and whose wives suffered from unexplained abortion or embryo abortion, and included another 46 normal healthy men present for pre-pregnancy check-up as controls. We examined the semen quality and sperm morphology, obtained the sperm DNA fragmentation index (DFI) by modified sperm chromatin dispersion, and measured the sperm DNA methylation level using the methylated DNA quantification kit and the colorimetric method. RESULTS: Compared with the normal controls, the men in the unexplained abortion group showed a significantly lower rate of big-halo sperm (ï¼»45.50 ± 26.27ï¼½ vs ï¼»36.49 ± 23.06ï¼½%, P = 0.038), a higher rate of abnormal-head sperm (ï¼»77.08± 12.21ï¼½ vs ï¼»81.09± 10.89ï¼½%, P = 0.049), and a lower level of sperm DNA methylation (ï¼»0.47 ± 0.33ï¼½ vs ï¼»0.36 ± 0.26ï¼½ ng/µl, P = 0.035). The sperm DNA methylation level was positively correlated with the percentage of big-halo sperm (OR=0.546, P<0.01). Multivariate regression analysis manifested that sperm head abnormality was an independent risk factor of early spontaneous abortion or embryo abortion (OR=1.032, P = 0.049), while the high methylation level was protective factor against early spontaneous abortion or embryo abortion (OR=0.244, P = 0.03). CONCLUSIONS: The abnormal level of sperm DNA methylation may be one of the important reasons for early spontaneous abortion or embryo abortion.