Propolis protects ovarian follicular reserve and maintains the ovary against polycystic ovary syndrome (PCOS) by attenuating degeneration of zona pellucida and fibrous tissue.

To examine the effects of 50 mg/kg and 150 mg/kg of propolis on ovarian folliculogenesis, p53 expression, and serum luteinising hormone (LH) and progesterone (P) levels in polycystic ovary syndrome (PCOS) modeled rats. Twenty-four Wistar female rats were divided into 4 experimental groups: Group 1 (G1, Control), Group 2 (G2, PCOS), Group 3 (G3, PCOS + 50 mg/kg propolis), and Group 4 (G4, PCOS + 150 mg/kg propolis). The PCOS model was induced via the administration of letrozole for 21 days. After 21 days, G3 and G4 received propolis (50 mg/kg or 150 mg/kg) by oral gavage for 10 days. Daily oestrous cycles were assessed to monitor PCOS formation. Histological examinations were carried out using haematoxylin and eosin (H&E) and Masson Trichrome (MT) staining. Ovarian follicles and corpus luteum (CL) structures were investigated. P and LH serum levels were determined by ELISA. A significant increase was observed in the number of cystic follicles in G2 compared to G1 (p < 0.001). Treatment with 50 mg/kg of propolis significantly ameliorated the elevated number of cystic and primary follicles seen in G2 (p < 0.001). Furthermore, G2 demonstrated a significant decrease in the number of CL structures (p < 0.05). Serum LH levels were significantly higher in G4 compared to both G1 and G2 (p < 0.01). No significant change was observed in circulating P levels. No p53 immunoreactivity was observed in any group. Low concentrations of propolis cannot completely improve the hormone profile and p53 expression associated with PCOS; however, these concentrations can control ovarian follicular cell architecture.