Beneficial effect of microsurgical varicocelectomy on human sperm DNA integrity

BACKGROUND: Human sperm DNA damage may adversely affect reproductive outcomes, and the spermatozoa of infertile men possess substantially more DNA damage than that of fertile men. To date, there is no available treatment for men with high levels of sperm DNA damage. The objective of this study was to examine the effect of varicocelectomy on sperm DNA denaturation (DD, an index of sperm DNA damage) in infertile men with a clinical varicocele. METHODS. We reviewed the reports of 37 men who underwent microsurgical varicocelectomy at our institution from September 2001 to July 2002. Standard semen parameters and the percentage of spermatozoa with DD (monitored by flow cytometry analysis of acridine orange-treated spermatozoa) were assessed before and 6 months after varicocelectomy. RESULTS. The percentage of spermatozoa with DD decreased following varicocelectomy compared with pre-operatively (27.7 versus 24.6%, respectively, P < 0.05). Sperm concentration and the percentages of motile sperm and normal forms (WHO criteria) increased following varicocelectomy, but the difference did not reach statistical significance. CONCLUSIONS. Our data suggest that varicocelectomy can improve human sperm DNA integrity in infertile men with varicocele. These data represent the first report of improved sperm DNA integrity after therapy and further support the beneficial effect of varicocelectomy on human spermatogenesis.