Fig. 2

The H&E-stained uterine sections revealed that hUCMSCs-EVs alleviate the inflammatory response in an experimentally induced IUA model in rats. In the control group, the endometrial surface is lined by high columnar epithelial cells (ECs) and round or oval uterine glands (UGs) in the submucosa and basal layer (a). The uterine cavity (UC) is widely opened (b). After 30 days of induction of IUAs, the surface in group II rats (IUAs group) was covered by flat and low columnar epithelial cells with few glands under the epithelial layer (c) and narrowing of the UC (d). In group III, the endometrial surface is lined by low columnar ECs and few numbers of UGs (e). The UC of group III is narrow (f). In group IV, the endometrial surface is covered by columnar ECs and an increased number of UGs (g). The UC of group IV is wide (h). In group V, the endometrial surface is lined by high columnar ECs and numerous UGs (i). The UC of group V is wide (j). Box blot of the mean number of endometrial glands in all groups (k); data are shown as mean ± SD, n = 5