Participation of the Cholinergic System in the Development of Polycystic Ovary Syndrome

Rosa Linares,Andrea Chaparro,Julieta A Espinoza,Deyra A Ramírez,Gabriela Rosas,Roberto Domínguez,Leticia Morales-Ledesma,Elizabeth Vieyra,Xóchitl N Acuña

doi:10.3390/molecules26185506

Abstract

In rats with polycystic ovary syndrome (PCOS) induced by injection of estradiol valerate (EV), unilateral or bilateral section of the vagus nerve restores ovulatory function in 75% of animals, suggesting that the vagus nerve participates in the development of PCOS. Since the vagus nerve is a mixed nerve through which mainly cholinergic-type information passes, the objective of the present study was to analyze whether acetylcholine (ACh) is involved in the development of PCOS. Ten-day-old rats were injected with 2.0 mg EV, and at 60 days of age, they were microinjected on the day of diestrus in the bursa of the left or right ovary with 100 or 700 mg/kg of ovarian weight atropine, a blocker of muscarinic receptors, and sacrificed for histopathological examination after the surgery. Animals with PCOS microinjected with 100 mg of atropine showed a lack of ovulation, lower serum concentrations of progesterone and testosterone, and cysts. Histology of the ovaries of animals microinjected with 700 mg of atropine showed corpus luteum and follicles at different stages of development, which was accompanied by a lower concentration of progesterone and testosterone. These results allow us to suggest that in animals with PCOS, ACh, which passes through parasympathetic innervation, is an important component in the persistence and development of the pathophysiology.

Highlights

Polycystic ovary syndrome (PCOS) is an endocrinopathy that, according to the Rotterdam consensus, has an incidence of 15 to 18%
10% of the animals treated with estradiol valerate (EV) and microinjected with 100 mg of atropine ovulated; when the microinjection was made in the left ovarian bursa, one animal ovulated five oocytes in the right ovary, and when they were microinjected in the bursa of the right ovary, one animal ovulated two oocytes in the right ovary
The results of the present study show that in animals with polycystic ovary syndrome (PCOS) induced by EV

Summary

Introduction

Polycystic ovary syndrome (PCOS) is an endocrinopathy that, according to the Rotterdam consensus, has an incidence of 15 to 18%. Based on the Rotterdam consensus, in women, the diagnosis of PCOS requires the presence of at least two of these criteria: the presence of clinical or biochemical hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology [1,2]. In the diagnosis of PCOS, some exclusion criteria for hyperandrogenism should be considered, including nonclassic adrenal hyperplasia, idiopathic hirsutism, and premature adrenarche [3]. An experimental model proposed to study PCOS is the administration of estradiol valerate (EV) to infantile or adult rats. Injecting 2 mg of EV into infantile or adult rats results in the interruption of the estrus cycle, persistent vaginal cornification, anovulation, the formation of follicular cysts, and high concentrations of testosterone [4,5,6]

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