MSC-exos protect TECs from apoptosis induced by I/R injury. (A) Representative confocal images of TUNEL staining in kidney tissues and quantification of the apoptotic cells (n = 6). Scale bars, 50 μm. (B) Western blotting of Bcl-2, cleaved-caspase-3, and Bax in kidney tissues (n = 4). (C) Flow cytometry analysis of annexin V/PI staining and quantification of the apoptotic cells (n = 3). (D) Representative images of TUNEL staining in HK-2 cells and quantification of the apoptotic cells per HPF (magnified 400×) (n = 10). Scale bars, 50 µm. (E) Western blotting analysis of Bax and Bcl-2 in HK-2 cells (n = 4). Data are presented as mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001 vs. sham group or control group, #p < 0.05, ##p < 0.01, ###p < 0.001, one-way ANOVA.