Verbascoside attenuates experimental varicocele-induced damage to testes and sperm levels through up-regulation of the hypothalamus-pituitary-gonadal (HPG) axis

Verbascoside (VB), which is found in many medicinal plant families, exhibits biological activities in various diseases. However, its effects on varicocele (VCL)-induced damage remain unknown.To investigate the effects and mechanism of VB on experimental rats with varicocele (VCL)-induced damage.Sixty sexually mature male Sprague-Dawley (SD) rats were divided into six groups (n = 10): control, control-sham, VCL-vehicle (normal saline), and VCL + VB groups (50, 100, and 200 mg/kg/day, intraperitoneally). After 4 weeks of VB treatment, all animals were sacrificed, and the body and testicular weight, sperm quality parameters, histopathology, antioxidant status, and hormone levels were tested. The levels of gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone in the hypothalamus were detected by western blot.Compared with the VCL-vehicle group (41.14%), administration of VB significantly increased the sperm viability (59.29, 65.45, 84.93%). VB groups showed higher Johnson's score (3.57 ± 0.15, 4.71 ± 0.26, 7.93 ± 0.37) than VCL-vehicle group (2.72 ± 0.24). Antioxidant status and hormone levels alterations were also observed. Meanwhile, the mean number of apoptotic tubules (8.15 ± 0.96, 6.61 ± 1.05, 2.17 ± 0.08) and apoptotic index showed a marked decrease. Compared with the VCL-vehicle group (0.21 ± 0.09), the VB groups (0.36 ± 0.07, 0.42 ± 0.06, 0.88 ± 0.10) showed considerable increases in GnRH.VB has protective effects on reproductive organs and VB may be therapeutically useful in the treatment of varicocele through up-regulation of the HPG axis.