Protective effect of hydro-alcoholic extract of Iranian propolis on the structure of neonatal rat ovary following stress

Introduction: Stress has various effects on body systems, including the nervous, endocrine, immune, reproductive and other systems, during neonatal life. The aim of this study was to investigate the effect of hydro-alcoholic extract of propolis on structural and evolutional changes in the neonatal rat ovary following weaning stress. Materials and Methods: female rats aged15 days (n = 48), weighing 15-20 g, were divided randomly into six groups of eight. Experiments started from the day 15 - 21 after birth. First group (negative control) included 21 days infants without any intervention, the second group (positive control) included infants received (0.1 ml) of saline solution daily and were not weaned all over the experiment, the third group (stress group) included infants who were separated from their mothers only six hours per day. The fourth, fifth and sixth groups of rats received daily weaning stress in addition to 50, 100 and 200 mg/kg of Propolis extract. 24 hours after the last injection, serum corticosterone levels were measured. The ovaries were removed and fixed. Sections prepared (5 micrometer) and stained by the methods of H;E and PAS. Histomorphometry was performed using a light microscope equipped with image analysis software. Results: Stress increased the newborn blood serum corticosterone levels and decreased the number of ovarian follicles and oocytes and increased the number of atretic ovarian follicles. However, hydro-alcoholic extract of propolis decreased the corticosterone levels in neonatal rat after stress, increased the number of ovarian follicles and oocytes and decreased the number of atretic ovarian follicles in neonatal rat following stress. Conclusion: This study showed that hydro- alcoholic extract of propolis strongly prevents structural changes in the newborn rat ovaries after stress