ABSTRACT
<p><b>OBJECTIVE</b>To investigate the biological characteristic of ectomesenchymal stem cells (EMSC) and the differentiation of p75(+)EMSC and influencing factors.</p><p><b>METHODS</b>The immunohistochemical staining method was used to observe the migration of EMSC from 12.5 d SD rat embryonic facial process. Then EMSC was labeled by p75 neurotrophin receptor, and the cell cycle and stem cell surface antigens of the p75(+) EMSC was examined.</p><p><b>RESULTS</b>Immunohistochemical staining showed that stem cells from the cranial neural crest migrated to embryonic rat facial process at 12.5 days. The sorting rate of the p75(+)EMSC was 6.1%. The proportion of the p75(+)EMSCs' S/G2/M phase was stable during subculture. The special substances CD29, CD146 and Stro-1 were marked for p75(+)EMSC, and the expressions of the markers were all higher (> 90%) in p75(+) EMSC.</p><p><b>CONCLUSIONS</b>The embryonic tooth did not start to grow on the conception 12.5 days of SD rats. The p75(+) EMSC after sorting had stable proliferation ability and had stem cell characteristics during subculture and didn't start differentiation.</p>