Experimental Diabetes-Induced Alterations in the Medial Preoptic Area and Copulatory Behaviour in Male Rats: A Histological and Behavioural Study

Diabetes mellitus is a major metabolic disorder frequently associated with secondary reproductive and sexual dysfunction in males. While peripheral complications are well documented, the contribution of central neural mechanisms remains less understood. This study investigated the effects of experimental diabetes on male copulatory behaviour and the morphology of the medial preoptic area (MPOA), a critical integration hub for sexual behaviour. Twenty male Wistar rats were divided into control and streptozotocin-induced diabetic groups. After 120 days, mating behaviour and penile reflexes were evaluated. Animals were then sacrificed, blood was collected for hormonal assays, and brain tissues were processed for histological and stereological analysis of the MPOA. Diabetic rats exhibited significantly elevated blood glucose levels alongside marked reductions in serum testosterone, FSH, and LH. Behavioural assessments revealed impaired copulatory performance, including significantly increased mounting, intromission, and ejaculatory latencies, accompanied by decreased mounting and intromission frequencies and depressed penile reflexes. Histological and Histomorphometrical analyses of the MPOA in diabetic subjects demonstrated significant reductions in neuronal diameter, volume, and numerical density compared to controls. Experimental diabetes induces structural degeneration within the MPOA alongside severe deficits in male copulatory behaviour and endocrine profiles. These findings indicate that diabetes-associated sexual dysfunction involves central neuroendocrine and hypothalamic pathology in addition to peripheral vascular and neuropathic factors.