Abstract: This study was purposed to investigate a techique to isolate mesenchymal stem cells from whole umbilical cord and their biological characteristics. Mesenchymal stem cells(MSCs) were isolated from umbilical cord(UC) by applying a explant technique and explanding cultured in vitro. Growth curves were drawn, and The phenotypes and cell cycle were evaluated by flow cytometry. UC-MSCs was induced to differentiate into adipocytes, osteocytes and chondrocytes in special differentiation condition. Mutidifferentiation related genes and stem cell-related transcription factors, Nanog, Oct-4, Sox-2 were detected by TR-PCR. The result indicated that UC-MSCs were easily isolated using a explant technique, and characteristic of plastic adherence and fibroblast-like morphology. the adherent cells displayed an abundant presence of CD73, CD90, CD105 and absence of CD34 , CD45 , HLA-DR. Cell cycle showed t hat there was percentage of stem cells as G0 / G81.56 % and S + G2 + M18.44% respectively. When cultured in differentiation media, they can be differentiated into adipocytes, osteocytes and chondrocytes. RT-PCR reactions confirmed that their mutidifferentiation related genes were positive.Moreover, stem cell-related transcription factors, Nanog, Oct-4, Sox-2 were positively expressed in UC-MSCs. Based on these findings, the explant technique method is a better method to obtain MSCs from whole human umbilical cord, and UC can be considered as a novel and convenient source of adult MSCs displaying high expansion potential and primitive pluripotent sten cells.

Key words: umbilical cord, mesenchymal stem cells, Differentiation, adipocytes , osteocytes, chondrocytes