hUMSC-derived exosomes alleviate follicular interstitial cell autophagy by let-7a-5p/AMPK/mTOR axis in POI rats.

Background: One major factor contributing to infertility in women of childbearing age is premature ovarian insufficiency (POI). Exosomes produced from human umbilical cord mesenchymal stem cells (hUMSC-Exos) have drawn a lot of attention lately as a potential treatment for ovarian dysfunction brought on by POI. However, its therapeutic mechanism is still unclear and needs further exploration.

Methods: POI model was established by intraperitoneal injection of cyclophosphamide (CTX) in female Wistar rats. These POI rats were treated with hUMSC-Exos for one week. In addition to in vivo experiments, in vitro POI models were also established. In vitro experiments, theca interstitial cells (TICs) treated with CTX were exposed to normal as well as let-7a-5p inhibitory hUMSC-Exos. The ovary structure, morphology, endocrine function, and reproductive ability of POI rats were observed by H&E staining and ELISA. Western blot, immunofluorescence staining (IF), and quantitative real-time polymerase chain reaction (qRT-PCR) were used to evaluate the autophagy-related indexes in ovary and TICs of POI rats in each group.

Results: CTX induced abnormalities of ovarian morphology, structure, endocrine, and reproductive function in rats, and accompanied by autophagy of TICs. Notably, hUMSC-Exos diminishes ovarian structural and functional damage in POI rats and TICs autophagy via targeting the AMPK/mTOR pathway. Furthermore, downregulating let-7a-5p in hUMSC-Exos weakened their ability to prevent TICs autophagy.

Conclusions: Overall, the findings suggested that hUMSC-Exos improves ovarian function in POI rats by inhibiting TICs autophagy via the let-7a-5p/AMPK/mTOR pathway. Our study provided further evidence that POI patients can benefit from hUMSC-Exos-mediated therapy.