Sperm Protamine mRNA Ratio and DNA Fragmentation Index Represent Reliable Clinical Biomarkers for Men with Varicocele after Microsurgical Varicocele Ligation

PurposeWe investigated whether the sperm protamine-1/2 mRNA ratio and DNA fragmentation index are reliable biomarkers in patients with clinical varicocele.Materials and MethodsWe performed a prospective study in 42 subfertile patients with left clinical varicocele and 10 normozoospermic healthy donors with proven fertility. All patients and female partners were seen 3 and 6 months after varicocelectomy for fertility examination. Real-time quantitative reverse transcriptase-polymerase chain reaction and SCSA® were performed to analyze the sperm protamine-1/2 mRNA ratio and DNA fragmentation index.ResultsThe protamine-1/2 mRNA ratio and DNA fragmentation index were significantly higher in the preoperative group than in the control group (p <0.01). After varicocelectomy in the pregnant group the protamine-1/2 mRNA ratio recovered to the normal value and the DNA fragmentation index was significantly lower than in the preoperative group (p <0.01). In the nonpregnant group the protamine-1/2 mRNA ratio and DNA fragmentation index did not differ (p >0.05). However, significant differences were present preoperatively according to varicocele severity in the protamine-1/2 mRNA ratio and DNA fragmentation index (p <0.05 and <0.01, respectively) with the highest values in the grade 3 group. Nevertheless, postoperatively no difference in varicocele severity was noted (p >0.05). The protamine-1/2 mRNA ratio was strongly related to preoperative and postoperative sperm concentration (Rs –0.238, p <0.01), progressive motility (Rs –0.327, p <0.01), total motility (Rs –0.206, p <0.05) and DNA fragmentation index (Rs 0.293, p <0.01) except for normal morphology (Rs –0.064, p >0.05).ConclusionsThe sperm protamine-1/2 mRNA ratio and DNA fragmentation index can effectively be used to evaluate male fertility. Male infertility due to varicocele may be associated with protamine deficiency and sperm DNA damage. The post-varicocelectomy protamine-1/2 mRNA ratio and DNA fragmentation index are associated with the post-varicocelectomy pregnancy rate.