Exosomal miR-433 regulates the secretion of inflammatory factors in endometrium epithelial cells of dairy cows with endometritis

Endometritis is a common postpartum reproductive system disease, which causes reproductive disorders and even infertility in dairy cows. High-throughput sequencing revealed that exosomal miR-433 is differentially expressed in the peripheral blood of dairy cows with endometritis. However, the specific roles of miR-433 in the occurrence and development of endometritis in dairy cows are still unclear. Therefore, a miR-433-labeled probe was used initially and found that miR-433 is mainly located in uterine cavity epithelial cells and stromal cells. The fluorescence expression of miR-433 in the uterine cavity epithelium and stromal tissues of dairy cows with endometritis is significantly weaker than that in the healthy tissues. The qRT-PCR results showed that the expressions of miR-433 in the uterine tissues of dairy cows with endometritis, LPS stimulated endometrial epithelial cells (EECs), and their derived exosomes were significantly lower than those in the uterine tissues of healthy dairy cows, EECs and their derived exosomes. Exosomal miR-433 derived from EECs transports into neighboring LPS-stimulated EECs by exosome vesicles fusion, regulating the secretion of inflammatory factors within the endometrial epithelium of dairy cows with endometritis, further influencing the development of endometritis. In conclusion, the intensity of miR-433 expression decreased cows during the occurrence of endometritis, which to some extent promotes the development and progression of endometritis in dairy cows.