OBJECTIVETo study the expression and distribution of hepatocyte-enriched transcriptional factors during the differentiation of hepatocyte by rat bone marrow stem cells in vitro.

METHODSMesenchymal stem cells were isolated from rat bone marrow and induced into mature hepatocyte in vitro. The mRNA expression levels of hepatocyte nuclear factor 4 alpha (HNF4 alpha), CCAAT enhancer binding protein (C/EBP) alpha and beta were compared between induced and non-induced cultures using semi-quantitative reverse transcription-polymerase chain reaction. The distribution pattern of HNF4 alpha was detected by immunofluorescence staining and observed by fluorescence microscope.

RESULTSTranscriptional factors HNF4 alpha, C/EBP alpha, and C/EBP beta were expressed in the induced cells during the culture process. The mRNA expression levels of HNF4 alpha and C/EBP alpha were significantly higher in induced cultures than those in non-induced cultures in the early stage, whereas C/EBP beta expression was significantly up-regulated in induced cultures at the late stage (P < 0.05). Immunofluorescence staining showed that HNF4 alpha was located in the cell nucleus of differentiated cells.

CONCLUSIONThe characteristic time-dependent expression of transcriptional factors HNF4 alpha, C/EBP alpha, and C/EBP beta during the hepatocyte differentiation by bone marrow stem cells demonstrates that the expressions of these transcriptional factors are closely related to the initiation and maintenance of hepatocyte differentiation.