OBJECTIVETo investigate the effects of intercellular adhesion molecule-1(ICAM-1) on the adherence between mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC).

METHODSMSC and EPC were isolated, cultured and expanded from the 6-8 weeks aged C57BL/6 murine bone marrow by in vitro. Immuno-fluorescence was used to detect the expression of ICAM-1 in MSC group, EPC group and co-cultured MSC and EPC group. The mRNA and protein levels of ICAM-1 were detected by RT-PCR and Western blot respectively, then, the ICAM-1 adherence between MSC and EPC was observed by adding different concentration of neutralizing antibody.

RESULTSThe expression of ICAM-1 on surface of MSC and EPC could be detected by cell immunofluorescence method. According to results of the semiquantitative fluorescene detection, the fluorescence strength of MSC+EPC co-cultured group (89.02 ± 24.52) was higher than that of MSC group (31.25 ± 2.95) and EPC group (34.32 ± 5.02), and there was statistical difference between them (P < 0.01), but there was no obvious difference between MSC group and EPC group (P > 0.05). RT-PCR detection showed that the expression levels of ICAM-1 in MSC+EPC co-cultured group were higher than that in MSC group and that in EPC group (P < 0.01), and expression level of ICAM in EPC group was higher than that in MSC group (P < 0.01). Western blot detection showed that the expression level of ICAM-1 protein in MSC+EPC co-cultured group (0.33 ± 0.4) was higher than that in MSC group (0.11 ± 0.01) (P < 0.05) and than that in EPC group (0.19+0.02) (P < 0.05), However, the expression level of ICAM-1 protein in EPC group was higher than that in MSC group (P < 0.05). The test of different concentrations against neutralizing antibody showed that with the increasing of concentration of ICAM-1 neutralizing antibody, the adhesion capability of MSC and EPC was gradually decreasing.

CONCLUSIONThe ICAM-1 can mediate the adherence process between MSC and EPC.