Figure 4

iMSCs-Exo regulated human umbilical vein endothelial cell (HUVEC) migration, proliferation, and tube formation. Migration of HUVECs was measured by using Real-Time Cell Analyzer (A, i, curve graph of RTCA; ii, Quantitative analysis of cell index at 4 h, 8 h, 12 h, 16 h, 20 h, 24 h for i.) and scratched wound assay (B, i, optical micrographs of scratched wound assay; ii, quantitative analysis of migration index at 12 h and 24 h for i.). Compared with the control group, iMSCs-Exo could improve the migration level of HUVECs (*P <0.05). Proliferation was measured by using the Cell Counting Kit-8 (CCK-8) (C). iMSCs-Exo can significantly stimulate HUVEC proliferation in a dose-dependent manner (*P <0.05). Tube formation test was performed on growth factor-reduced Matrigel (D, i, optical micrographs of tube formation assay; ii, quantitative analysis of total tube length at 4 h, 6 h, 18 h for i; iii, quantitative analysis of total branch points at 4 h, 6 h, 18 h for i.). There was no significant difference in branch number and total tube length of the capillary-like structures for HUVECs cultured in low serum growth supplement (LSGS), 50 μg/mL, or 100 μg/mL iMSCs-Exo at 4 and 6 hours (P >0.05). However, after being cultured for 18 hours, HUVECs cultured in 100 μg/mL iMSCs-Exo formed more capillary-like branches (*P <0.05), and the total tube length of the capillary-like structures was much longer than that cultured in LSGS or 50 μg/mL iMSCs-Exo (*P <0.05). HUVECs cultured in control medium hardly formed capillary-like structures. iMSCs-Exo, exosomes derived from induced pluripotent stem cell-derived mesenchymal stem cells; M200, Medium 200.