Possible Synergistic Modulation of Hormonal Balance and Ovarian Structure by Clomiphene–Letrozole Co-Administration in a Rodent Model of Hyperandrogenism

Abstract Infertility, defined as the inability to achieve pregnancy after 12 months of unprotected intercourse, is a major reproductive health concern. In females, hyperandrogenism often contributes to polycystic ovarian syndrome (PCOS), a leading cause of infertility. Although clomiphene and letrozole are widely used as ovulation inducers, their individual efficacy is limited, and the potential benefit of combined therapy remains unclear. This study investigated the effects of clomiphene–letrozole co-administration on gonadotrophic hormones, inflammatory cytokines, antioxidant status, and ovarian histomorphology in a rat model of hyperandrogenism. Thirty female Wistar rats were randomised into five groups (n=6). Group A received saline, while groups B–E were administered testosterone enanthate (10 mg/kg, subcutaneous injection) for 35 days to induce PCOS. Group B served as PCOS control, while groups C, D, and E were additionally treated with clomiphene (100 µg/kg), letrozole (5 mg/kg), or their combination, respectively, for 10 days from day 36. Hormonal assays, cytokine profiling, antioxidant measurements, and ovarian histology were performed. Results showed that the co-administration significantly reduced body and ovary weights, lowered glucose levels, and improved oestradiol and follicle-stimulating hormone profiles compared with PCOS controls. Combination therapy also enhanced antioxidant capacity, reduced lipid peroxidation, and modulated inflammatory cytokines by lowering IL-1β and TNF-α while elevating IL-10. Histological evaluation revealed cystic follicles with basement membrane thickening in the PCOS control, consistent with ovarian hyperstimulation; and a reversal with clomiphene and or letrozole treatment. In conclusion, clomiphene–letrozole co-administration demonstrated superior benefits over monotherapy in modulating endocrine, oxidative, and inflammatory parameters, suggesting a potential therapeutic advantage in ovulation induction for PCOS-related infertility.