Anti-polycystic ovary syndrome effect of electroacupuncture: IMD inhibits ER stress-mediated apoptosis and autophagy in granulosa cells

Polycystic ovary syndrome (PCOS) is a complicated endocrinopathy affecting women at reproductive age. Increasing evidence has shown the anti-PCOS effect of electroacupuncture (EA), a modified approach of traditional Chinese medical therapy “acupuncture”. However, the underlying mechanism of EA-alleviated PCOS waits further explored. In this study, experimental PCOS were induced in rats by dehydroepiandrosterone (DHEA) injection. Testosterone (T)-induced human ovarian granulosa cell (GC) line KGN was used to mimic PCOS in vitro . EA significantly alleviated histological changes and hormone disruption in PCOS rats. Besides, EA inhibited cell apoptosis, autophagy and the activation of endoplasmic reticulum (ER) stress-related PERK/eIF2α/ATF4/CHOP signaling in ovaries of PCOS rats. More interestingly, intermedin (IMD), a member of calcitonin gene-related peptide (CGRP), was evidently up-regulated in ovarian GCs after EA treatment, and its main bioactive form IMD 1-53 suppressed cell apoptosis, autophagy and PERK/eIF2α/ATF4/CHOP signaling in T-induced KGN cells. Consistent with IMD 1-53 , ER stress inhibitor 4-PBA exerted an inhibitory effect on T-induced cell apoptosis and autophagy in KGN cells. Collectively, this study validates the protective effect of EA on DHEA-induced PCOS, and proposes that IMD relieved apoptosis and autophagy in T-induced granulosa cells via inhibiting ER stress.