Beneficial effects of microsurgical varicocoelectomy on sperm maturation, DNA fragmentation, and nuclear sulfhydryl groups: a prospective trial

Abstract

There is evidence to show that varicocele repair can improve conventional sperm parameters but the effects on sperm chromatin integrity have not been fully elucidated. We sought to examine the effects of varicocelectomy on sperm maturation, nuclear chromatin integrity and nuclear sulfhydryl groups. We conducted a prospective study of consecutive infertile men (n=29) that underwent a microsurgical sub-inguinal varicocelectomy for treatment of a clinically palpable varicocele and abnormal semen parameters. Six healthy sperm donors served as controls. We evaluated conventional sperm parameters and markers of sperm chromatin and DNA integrity (aniline blue (AB) staining, iodoacetamide fluorescein (IAF) fluorescence and, % DNA fragmentation index (%DFI) and percent high DNA stainability (%HDS) by sperm chromatin structure assay) before and 6 months after surgery. The sperm %DFI, %HDS, % 5-IAF staining (diffuse head staining) and % 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 2.5 vs. 13.5% respectively). The %HDS and %DFI decreased significantly after surgery (from 10% to 6% and from 20% to 13%, respectively). Similarly, the %5-IAF and %AB staining also decreased significantly after surgery (from 16.3% to 5.4%, and from 13.5% to 5.4%, respectively). We observed significant inversely relationships between sperm progressive motility and both %IAF staining and %DFI (r=-0.44 and -0.43, respectively). The data show that varicocelectomy is associated with an improvement in sperm DNA integrity and chromatin compaction using three different assays of sperm chromatin integrity.