Fig. 3

BMMSC-sEV restore urethral function and structure in SUI rats. a Detection of the urethral muscle layer by α-SMA staining. The smooth muscle was stained red. Scale bar, 500 μm. b HE staining of the urethral sections. Scale bar, 500 μm. c The elastic fibers were visualized by EVG staining. Elastic fibers were stained black. Scale bar, 100 μm, 50 μm. d Evaluation of collagen fibers under a polarization microscope by Sirius red staining. Collagen I was stained orange or red. Collagen III was stained green. Scale bar, 100 μm. e The mean values of the LPP of the BMMSC-sEV group and the BMMSC group were higher than those of the sham group and NRK-52E-sEV group, respectively, while no differences were detected among the BMMSC-sEV group, the BMMSC group, and the intact control group. f The area fraction of red fluorescent signals in α-SMA staining. g The average thickness of smooth muscle layers in HE staining. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001