Fig. 2

The migration and endothelial differentiation of MSCs in vivo and in vitro. a Local cell migration to irradiated aortas was traced by GFP label. The GFP-labeled MSCs were visible in the neointima, suggesting cell implantation in the irradiated aortas. RT + MSC-H group had a larger population of migrated cells than RT + MSC-C group. The ECs in the neointima were identified by CD31. The majority of migrated cells from MSC-H group expressed CD31. b The levels of Sry gene in the aortas were measured by quantitative PCR. RT + MSC-H group yield a higher level of Sry gene than the RT + MSC-C group. The assay was repeated three times for each sample, and the RNA level was expressed in the fold change to that of RT + MSC-C group. Group comparison was made by using Student’s t test. *P < 0.05. c The percentage of CD31-positive cells in migrated MSCs were calculated and compared between groups. RT + MSC-H group had a higher percentage of migrated cells expressing CD31 than RT + MSC-C group. Five random high-power fields were examined in the sections of the aorta for each rat, and CD31-positive GFP-labeled cells were counted to determine the percentage of migrated cells expressing CD31. The average percentage was calculated from eight rats for each group. Group comparison was made using the Mann-Whitney test. *P < 0.05. d In vitro endothelial differentiation of MSCs was generated by EC-MSC coculture system. The ECs were identified by CD31. A greater number of MSC-H cells differentiated to ECs than MSC-C cells on day 14. e The RNA levels of CD31 in MSCs were measured by quantitative PCR during the coculture. A gradual increase of CD31 RNA levels was acquired by both MSC-C and MSC-H cells from day 7 till day 14. In comparison, MSC-H cells yielded higher levels of CD31 RNA than MSC-C cells since day 7. The assay was repeated three times for each sample, and the RNA level was expressed in the fold change to that of day 0. Group comparisons were made by using Student’s t test. *P < 0.05