Thermosensitive hydrogel as a sustained release carrier for mesenchymal stem cell-derived extracellular vesicles in the treatment of intrauterine adhesion

Intrauterine adhesion (IUA), a prevalent etiology of female infertility, is attributed to endometrial damage. However, conventional therapeutic interventions for IUA are plagued by high recurrence rates. Human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUCMSC-EVs) demonstrate the promising therapeutic effects on IUA, but the current efficacy of extracellular vesicles (EVs) is hindered by lower retention and bioavailability. In this study, a thermosensitive hydrogel was utilized as a prolonged release carrier to improve the retention and bioavailability of hUCMSC-EVs in IUA treatment. The hydrogel-EVs complex effectively prolonged EVs retention in human endometrial stromal cells and an IUA mouse model. The complex exhibited superior protection against cellular injury, significantly alleviated endometrial damage, inhibited fibrosis, suppressed inflammation, and improved fertility compared to EVs alone. The results indicated that thermosensitive hydrogel enhanced the therapeutic capacity of EVs for IUA by prolonging their retention in the uterine environment. The hydrogel-EVs complex provides a novel strategy for the sustained release of hUCMSC-EVs in the treatment of IUA.