Leptin and varicocele-related spermatogenesis dysfunction: animal experiment and clinical study

The objective of this study was to explore the relationships between varicocele-related spermatogenesis dysfunction and the expression of leptin and leptin receptors. In rats with experimental varicocele, the function of spermatogenesis, the expression of leptin and leptin receptors in testes were analysed; and in patients with varicocele-related male infertility, serum and seminal plasma levels of leptin, gonadal hormones and semen parameters were evaluated. In the testes of rats, leptin was expressed in seminiferous tubules and intersitium, leptin receptor was predominantly expressed in interstitium. The expression of leptin and its receptor in the testis of rats was not related to the weight of rat, but was inversely related to the weight of testis (r = -0.408, p = 0.009 and r = -0.433, p = 0.005, respectively), the Johnsen scores (r = -0.916, p = 0.000 and r = -0.863, p = 0.000, respectively), the seminiferous tubules diameter (r = -0.853, p = 0.000 and r = -0.870, p = 0.000, respectively) and the thickness of seminiferous epithelium (r = -0.929, p = 0.000 and r = -0.948, p = 0.000, respectively). In varicocele patients (N = 40), the sperm concentration and motility were significantly lower (p = 0.000) than those in the control group (N = 25), and the leptin level in seminal plasma was significantly higher (p = 0.000) than that in the control group. The leptin in serum and seminal plasma was positively related (r = 0.223, p = 0.002). The seminal plasma leptin level was inversely related to sperm concentration (r = -0.632, p = 0.000) and motility (r = -0.635, p = 0.000). There was no significant relation between serum leptin and seminal parameters and between leptin and gonadal hormone values. The dysfunction of spermatogenesis in varicocele-related infertile male is associated with increase in leptin and leptin receptors. Leptin may have local effects on the function of testis and spermatogenesis.