Protective effect of platelet-rich plasma against structural and functional changes of the adult rat testis in carbimazole-induced hypothyroidism

Objective: Hypothyroidism (HT) influences spermatogenesis and is associated with male infertility. Platelet-rich plasma (PRP), a biological product rich in growth factors, promotes tissue repair. In this study, the likely protective effects of PRP on testicular tissue damage in carbimazole (CBZ)-induced HT were evaluated. Methods: Forty male rats were divided into four groups. HT was induced by administering CBZ (1.35 mg/kg orally, for 45 days). Two doses of PRP (40 µL each, locally injected into the testis on days 15 and 30) were also given. After 45 days, blood samples were taken from the heart to measure triiodothyronine (T3), thyroxine (T4), and testosterone levels, and semen analysis was performed. For stereological assessment, the left testis was removed, fixed, embedded, sectioned, and stained with hematoxylin and eosin. The right testis was excised to evaluate antioxidant levels. Results: CBZ was demonstrated to induce HT, characterized by significant reductions in T3 and T4. HT was associated with decreased testicular weight, impaired sperm parameters, reduced testosterone concentration, diminished antioxidant activity, reduced volumes of testicular components, and lower total numbers of testicular cells of various types. When HT samples were treated with PRP, improvement was observed for all of these changes. This protective effect could be attributed to the growth factors present in PRP. Conclusion: PRP appears to prevent the structural changes in the testes and the deterioration in sperm quality caused by CBZ-induced HT. This protective effect is likely due to mitigation of oxidative damage and elevation of testosterone levels.