Abstract: miRNAs are a group of small, non-coding RNAs regulating gene expression at the post-transcriptional level. The altered miRNA levels are associated with diabetes and other disorders related with insulin resistance, meanwhile there are many miRNAs at the detectable level in their blood and follicular fluid of PCOS patients, suggesting that those miRNAs could serve as potential biomarkers of PCOS. The expression levels of four miRNAs: miR-21, miR-27b, miR-103 and miR-155, in circulating blood of those obese PCOS patients were significantly increased, and other three miRNAs, miR-222, miR-146a and miR-30c, have also been studied as potential serum biomarkers of PCOS. Interestingly, many miRNAs were detected in the follicular fluid. The expression levels of miR-132 and miR-320 were significantly decreased, while other three miRNAs, miR-224,miR-376a and miR-143, could also be developed as new targets for the PCOS pathophysiological study. It is necessary to study further those miRNAs as potential targets of PCOS pathophysiological mechanism, due to the heterogeneity of PCOS and the differences in miRNAs profiles from the present studies.

Key words: Polycystic ovary syndrome, MicroRNAs, Biological markers, Insulin resistance