A systematic review on the effect of microplastics on the hypothalamus-pituitary-ovary axis based on animal studies

Humans are exposed to microplastics through three routes: oral, dermal, and respiratory. These tiny polymer particles enter the body and accumulate in various organs. One of the most sensitive organs to microplastics is the female reproductive system. In this review, manuscripts that investigated the effects of various microplastics on the hypothalamic-pituitary-ovarian axis in laboratory animals were collected with relevant keywords. This axis plays an important role in the function of the female reproductive system. Effects on endpoints of this axis, including hormonal changes, gene expression, and histopathological changes, were assessed. The most studied microplastic was polystyrene. Hormone levels were measured in all studies. In almost all studies, 17β-estradiol was decreased. Apoptosis and oxidative stress-induced damage in the ovaries were also observed in some studies. The results summarized from the manuscript emphasize the adverse effects of microplastics, especially polystyrene microplastics, on the female reproductive system following exposure.