Short and long-term effects of experimental varicocele.

Background: Varicocele is associated with a progressive decrease in male fertile potential, but it has yet to be determined if the duration of varicocele is associated with altered sperm functional quality.

Objectives: This experimental study investigated the time-dependent effects of varicocele on spermatogenesis, sperm parameters, and sperm functional traits.

Materials and methods: Thirty-five mature male Wistar rats (200 ± 25 g) were included. After 2 weeks of adaptation, rats were randomly divided (n = 7/group) into control, 2 months sham (sham-2), 2 months varicocele (VCL-2), 4 months sham (sham-4), and 4 months varicocele (VCL-4) groups. Cauda epididymides were incised transversally and incubated in Biggers-Whitten-Whittingham media at 37°C for 30 min. Sperm concentration, motility, morphology, viability, mitochondrial activity (3,3' diaminobenzidine staining), acrosome integrity (PNA-FITC), and DNA fragmentation (alkaline Comet assay) were determined. Histological analysis on testicular cross-sections was performed using H&E staining, and Johnsen's score was determined for each sample.

Results: Decreased Johnsen score, sperm count, motility, viability, normal morphology, and mitochondrial activity were observed in VCL-2 and VCL-4 groups when compared with sham-2, sham-4, and control groups. Higher levels of acrosome damage and DNA fragmentation were observed in VCL-2 and VCL-4 groups compared to sham and control groups. A negative correlation was observed between Johnsen scores and acrosome damage (r = -0.7690; p < 0.0001), and a positive correlation was observed between Johnsen scores and sperm DNA fragmentation (r = 0.8333; p < 0.0001). No differences were observed between the VCL-2 and VCL-4 groups in any of the analyses.

Discussion and conclusion: Experimental varicocele leads to decreased semen quality, sperm functional integrity, and Johnsen's scores. Moreover, to our knowledge, this is the first study demonstrating a direct association between spermatogenesis and sperm count, motility, acrosomal integrity, and DNA fragmentation levels in experimental varicocele. Longer periods of varicocele did not potentiate the negative effects, in this study.