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 (［45.50 ± 26.27］ vs ［36.49 ± 23.06］%, P = 0.038), a higher rate of abnormal-head sperm (［77.08± 12.21］ vs ［81.09± 10.89］%, P = 0.049), and a lower level of sperm DNA methylation (［0.47 ± 0.33］ vs ［0.36 ± 0.26］ 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.
目的： 探索精子DNA甲基化水平异常与早期自然流产的关系。方法： 随机选取98例符合纳入标准的配偶不明原因流产或胚停育男性为研究对象，另选取健康孕前体检男性46例作对照。行精液常规、精子形态分析，以改良精子染色质扩散法检测精子DNA碎片化指数。精子DNA甲基化水平检测采用甲基化定量试剂盒，运用比色法检测。 结果： 与对照组相比，早期不明原因流产组大晕环精子百分率［(45.50 ± 26.27)% vs (36.49± 23.06)%］ 显著降低（P = 0.038），精子头部异常比例［(77.08± 12.21)% vs (81.09± 10.89)%］显著增高（P = 0.049），精子DNA甲基化水平［(0.47 ± 0.33) vs (0.36 ± 0.26) ng/μl］显著降低（P = 0.035）；并且精子DNA甲基化水平与大晕环精子百分率呈正相关（r = 0.546, P lt;0.01）。多因素回归分析显示，精子头部异常是早期自然流产/胚停育的独立危险因素（OR=1.032，P =0.049），而精子高甲基化水平是早期自然流产/胚停育的保护因素（OR=0.244，P = 0.03）。 结论： 精子DNA甲基化水平异常可能是不明原因早期自然流产或胚停育的原因之一。.
Keywords: DNA methylation; big halo; sperm; spontaneous abortion.