The influence of indole propionic acid on molecular markers of steroidogenesis, ER stress, and apoptosis in rat granulosa cells exposed to high glucose conditions

Hyperglycemia is known as one of the main causes of infertility in human societies. Indole propionic acid (IPA) is produced by intestinal microbiota and has antioxidant and anti-inflammatory properties. This study aims to investigate the effects of IPA on molecular indices of steroidogenesis, ER stress, and apoptosis induced by high glucose (HG) in granulosa cells. Primary GCs, isolated from ovarian follicles of Rats were cultured in 5 mM (control) and 30 mM (HG) of glucose and in the presence of 10 and 20 µM of IPA for 24 h. The cell viability was assessed by MTT. The gene expression of P450SCC, 3βHSD, CYP19A, BAX, BCL2, and STAR was evaluated by Real-Time PCR. Protein expression of ATF6, PERK, GRP78, and CHOP determined by western blot. Progesterone, estradiol, IL-1β, and TNF-α were measured by ELISA. HG decreased the viability, and expression of P450SCC, 3βHSD, CYP19A, BCL2, STAR, and increased BAX. 10 and 20 µM of IPA increased cell viability, expression of P450SCC, 3βHSD, CYP19A, BCL2 and STAR and decreased BAX compared to the HG group. The expression of ATF6, PERK, GRP78, and CHOP proteins increased by HG and IPA decreased the expression of these proteins compared to the HG group. Also, HG decreased progesterone and estradiol levels and increased IL-1β and TNF-α. IPA significantly increased progesterone and estradiol and decreased IL-1β and TNF-α compared to the HG group. IPA can improve the side effects of HG in GCs of rats, as responsible cells for fertility, by improving steroidogenesis, regulation of ER-stress pathway, suppression of inflammation, and apoptosis.