Disturbed Gastrointestinal Contractility in a Polycystic Ovary Syndrome Rat Model

Background: Polycystic ovary syndrome (PCOS), a common hormonal disorder in women, affects 4–18% of women of reproductive age worldwide. A higher prevalence of irritable bowel syndrome was found in women with PCOS. However, the effects and mechanism of PCOS on stomach and colon contractility remain unclear. Aims: This study aims to evaluate the correlation between PCOS and gastrointestinal disorder. Methods: Four-week-old female rats were subcutaneously implanted with pellets containing 7.5 mg of dihydrotestosterone for 13 weeks to create PCOS rat models. After vaginal smears, the estrus cycle stage was evaluated. Oral glucose tolerance test was performed after 90 days of treatment. All animals were killed at 17 weeks. The rats were fasted overnight and then anesthetized before decapitation, and the stomach fundus and colon were surgically removed and cultured in oxygenated Krebs solution. Acetylcholine and carbachol were used to evaluate the cholinergic system on contractility. Results: The basal and stomach fundus responded with a reduced frequency and contractility in response to acetylcholine in the PCOS group. Moreover, no difference was found in the spontaneous stomach contractility induced by carbachol in both groups. Lower maximal colon muscle contractility was also found in response to acetylcholine stimulation in PCOS rats. Furthermore, lower maximal muscle contractility was found in response to extracellular calcium levels. MLC20 phosphorylation was also reduced in the gastrointestinal tissue in PCOS rats. Conclusions: PCOS induces gastroparesis and reduces gastrointestinal muscle contractility. This effect is, at least partly, through reducing the responsiveness of acetylcholine and MLC20 phosphorylation.