Utilizing follicular fluid on endometrial stromal cells enhances decidualization by induced inflammation

Background Polycystic ovary syndrome (PCOS) is a disease associated with inflammation and the follicular fluid of this patient contains proinflammatory cytokines. Abdominal obesity (AO) is also linked to increased levels of proinflammatory cytokines. This study investigated the induction of inflammation and decidualization of in vitro cultured endometrial stromal cells (ESCs) obtained from women with a normal uterus using the follicular fluid of PCOS and non-PCOS patients with or without abdominal obesity. Methods and results Forty patients under 35 years old, referred to the Royan Institute, were divided into four groups: PCOS with AO, PCOS without AO, non-PCOS with AO, and non-PCOS without AO. Follicular fluid samples were added to the culture medium of ESCs for each group. The rate of decidualization was measured by examining decidual markers. The study also investigated morphological changes in uterine endometrial cells, cell migration rates, and gene expression across all groups. We found that the non-PCOS group without AO had the highest decidualization potential and the highest expression of decidualization markers ( P ≤ 0.05). Groups with an inflammatory phenotype of PCOS or abdominal obesity showed the highest expression of decidual pathway markers. The expression levels of inflammatory and proliferative markers in the PCOS group with AO were significantly higher than in the other groups ( P ≤ 0.05). Conclusions The inflammatory profile present in the follicular fluid may trigger the decidualization process. Consequently, in the future, follicular fluid could be utilized as a natural supplement with human cells to promote decidualization and enhance endometrial receptivity in assisted reproductive technology. Graphical Abstract