Context-dependent effects of whole-body vibration on reproductive function and penile tissue integrity in sedentary male rats.

Sedentary behaviour is increasingly recognized as a risk factor for systemic disorders; however, its effects on male reproductive health and penile tissue integrity remain insufficiently understood. Furthermore, the therapeutic role of whole-body vibration (WBV) has not been investigated. This study evaluated the effects of sedentary behaviour on testicular and penile tissues and examined whether WBV could attenuate these alterations. We hypothesized that sedentary behaviour would impair spermatogenesis and penile tissue integrity, whereas WBV would attenuate these effects. Thirty-two male Wistar rats were randomized into four groups (n = 8/group): Control, Sedentary, Sedentary+WBV and WBV. Sedentary conditions were induced for 28 days via a reduced-cage model, with daily WBV application (45 Hz, 3 mm). Serum testosterone, sperm parameters, testicular histology and penile smooth muscle-to-collagen ratio were assessed. Sedentary behaviour impaired spermatogenesis, with lower Johnsen scores (P = 0.008), reduced sperm concentration (P = 0.006) and motility (P < 0.001), and increased morphological abnormalities (P < 0.001). It also reduced the penile smooth muscle-to-collagen ratio (P < 0.001), indicating adverse structural remodelling in erectile tissue. In sedentary animals, WBV attenuated several alterations, preserving sperm quality and cavernosal smooth muscle content. However, WBV alone impaired spermatogenesis and increased sperm morphological abnormalities in non-sedentary animals. Serum testosterone levels did not differ significantly. In conclusion, prolonged sedentary behaviour impaired male reproductive indices and induced adverse structural remodelling of penile tissue in male rats. WBV showed context-dependent effects, attenuating alterations under sedentary conditions while showing adverse associations in non-sedentary animals. These findings warrant further translational investigation into the context-dependent effects of WBV on male reproductive and penile tissues.