sEV-mediated transfer of miR-21 promotes HCEC proliferation and migration. (a, b) HCECs were treated with miR-21 KD HUMSC-sEVs or miR-21 contained HUMSC-sEVs for 18 h. The scratch assay showed the healing of the miR-21 KD HUMSC-sEV-treated group was slower than the miR-21 contained HUMSC-sEV-treated group, n = 5. (c) The CCK-8 assay showed the proliferation of the miR-21 KD HUMSC-sEV-treated group was lower than the miR-21 contained HUMSC-sEV-treated group after 18 hours, n = 3. (d, e) The proliferation of HCECs was detected by EdU incorporation after transfected with miR-21 mimics (at final concentration of 50 nM). Blue: nuclear staining (Hoechst33342); red: EdU staining, n = 3. (f) The CCK-8 assay showed the proliferation of the miR-21 mimic group was higher than control group after 48 hours, n = 3. (g, h) The scratch assay showed significantly faster wound closure in HCECs incubated with miR-21 mimics than NC after 18 hours, n = 5. Data are expressed as the means ± SD. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001. KD: knockdown.