Effects of microsurgical varicocelectomy on human sperm DNA fragmentation, distribution of nuclear sulfhydryl groups and sperm maturation: a prospective trial

Abstract

To examine the effect of varicocelectomy on sperm quality, specifically, sperm nuclear chromatin integrity, distribution of nuclear sulfhydryl groups and sperm maturation. A prospective trial. We prospectively evaluated a consecutive series of infertile men (n=29) presenting to Ovo clinic with one year or more history of infertility, a clinically palpable varicocele and abnormal semen parameters. Six sperm donors with normal sperm parameters served as controls. Conventional sperm parameters, sperm nuclear DNA integrity (sperm chromatin structure assay), distribution of nuclear sulfhydryl groups (Iodoacetamide fluorescein stain “5-IAF”) and sperm maturation (Aniline Blue stain “AB”) before and 4 months after microsurgical varicocelectomy. The percentage of spermatozoa with the sperm %DFI, %HDS, positive 5-IAF staining (diffuse and intense head staining), positive AB staining (dark blue) were all significantly lower in the control group compared to infertile men with varicocele (8 vs. 20%, 4.0 vs. 9.6%, 1.7 vs. 16.3%, and 13.5 vs. 2.5% respectively). The percentage of spermatozoa with positive 5-IAF nuclear and positive AB staining decreased significantly after surgery (16.3 to 5.4%, and 13.5% to 5.4% respectively). Similarly, the %HDS and %DFI also decreased significantly after surgery (from 10% to 6% and from 20% to 13%, respectively). The only notable relationships were between aniline blue staining and HDS post varicocelectomy (r=0.57, P<0.05), and both IAF staining and %DFI were inversely correlated with motility (r=-0.44 and -0.43, respectively). The data show that varicocelectomy is associated with a consistent improvement in sperm DNA integrity and chromatin compaction using three different cytochemical assays of sperm chromatin integrity (SCSA, IAF, Aniline Blue).