RESUMO
Objective To study the aberrant DNA methylation of H19 and MEST in infertile male sperm.Methods Routine semen analysis and morphological analysis were performed on 15 control individuals and 33 oligoastheno-teratozoospermias.Sperms were purified by density gradient centrifugation and DNA was extracted and treated with bisulfite.After PCR,the purified PCR products were cloned into pMD (R)18-T vector and proceed to chemical transformation,restriction enzyme reaction.For each sample,positive clones were selected for sequencing analysis and DNA methylation analysis.Results Five control individuals had high degree of H19 and methylation rate was 100.0％,while the methylation rate of 93.0％ in 10 oligoastheno-teratozoospermias was significantly lower.Significant difference was found in methylation rate between the control individuals and oligoastheno-teratozoospermias (P ＜ 0.01).As to MEST,10 control individuals had a low degree of MEST and the methylation rate was 1.6％,while the methylation rate in 23 oligoastheno-teratozoospermias was 4.8％.No significant difference was found in the methylation rate between control individuals and oligoastheno-teratozoospermias (P ＞ 0.05).Conclusion Male infertility is associated with aberrant methylation of H19 differentially methylated region,and it may be a biomarker of human spermatogenesis defect.