Sperm DNA damage:an independent parameter for evaluation of sperm quality

Objective:To analyze the relationship between sperm DNA damage assessed by sperm chromatin dispersion(SCD) and parameters of routine semen analysis.Methods:1098 cases of male infertility were examined by routine semen analysis and SCD for detection of sperm DNA fragmentation as expressed DNA fragmentation index(DFI).The relationship between DFI and sperm concentration,motility,and morphology were analyzed.Results:4.9% case with normal param-eters of routine semen analysis had DFI 30% and 72.3% cases with at least one abnormal parameter had DFI 30%.There were significant differences of age,abstinence duration,total amount of sperm,total amount of mobile sperm,D grade sperm,normal morphology,head defect,neck defect,and tail defect among the three groups classified as DFI20%,20～30% and ≥30%.The correlative analysis showed DFI was moderate or weak positive correlation to age,abstinence duration,D grade sperm,head defect,neck defect,and tail defect(r=0.118,0.109,0.572,0.217,0.311 and.278,respectively),but negative corre-lation to total amount of sperm,total amount of mobile sperm,and normal morphology(r =-0.224,-0.345 and-0.303,respectively).The stepwise linear regression showed age,abstinence duration,D grade sperm and neck defect were independent variables related to DFI.Conclusion:Sperm DNA damage has moderate or weak correlation to parameters of routine semen analysis.In some cases of male infertility,sperm DNA damage may be an independent parameter to evaluate sperm quality.