Effects of vitamin E on ovarian tissue of rats following treatment with p-nonylphenol: A stereological study

Background: Para-Nonylphenol (p-NP) is one of the environmental pollutants which cause reproductive system disorders. Objective: The effects of vitamin E on ovary structure during its development in rats treated with p-NP. Materials and Methods: 32 Wistar female rats after mating were divided into 4 groups; control, vitamin E (100mg/kg/day), p-NP (250mg/kg/day) and p-NP + vitamin E. The rats were treated from the day 7 of pregnancy till 21(st) day of postnatal through sucking period. After weaning, the female pups were treated by gavages for 120 days. The total volume of ovary, number of follicles, volume of oocyte, follicular cells and their nuclei and the thickness of zona pellucida were estimated stereologically. The results were analyzed using one way ANOVA and p<0.05 was considered significant. Results: The ovary weight, mean total volume of ovary and cortex, number of antral and graafian follicles and body weight were decreased significantly (p<0.05) in the p-NP treated rats compared to control and other groups, while the number of atretic follicles was increased significantly (p<0.05). A significant reduction (p<0.05) in volume of oocyte, follicular cells and their nuclei in antral and graafian follicles was found in p-NP group. In addition, treatment with only vitamin E showed an improving effect on folliculogenesis due to a highly significant increase (p<0.01) in the number of primordial follicles. Conclusion: Vitamin E could compensate the adverse effects of p-NP on the ovary structure during its development.