miRNA-21-5p mimics facilitated survival and inhibited apoptosis in CMECs and enhanced angiogenesis in vitro. A: The cell viability of CMECs transfected with miR-21-5p mimics, scramble, CT-exos or blank under normoxic and ischemic-hypoxic conditions. B: Annexin V/PI staining and flow cytometry assay of miR-21-5p mimic-, scramble-, CT-exos-, and blank-treated CMECs cultured under normoxic and ischemic-hypoxic conditions for 24 h. C: Tube formation assay of CMECs transfected with miR-21-5p mimics, scramble, CT-exos and blank. The above studies (A-C) were conducted using two animals in at least three repeat experiments for each individual animal. **: p< 0.01, #: p < 0.05 compared with the blank group and scramble group, &: p < 0.05 compared with the miR-21-5p group.