Abstract: Objective:To investigate the potential of directed differentiation of fetal liver stem cells (FLSCs) in mice with sponataneous green fluorescence in vitro and in vivo.
Methods:FLSCs were taken from green fluorescent protein transgenic mice at embryonic day 13. After mechanical dissection and enzyme digestion with collagenase, FLSCs were further cultured. The expression of stem cell related markers and the self renewal ability were identified by flow cytometry. The expression of alpha fetoprotein (AFP) was detected by RT PCR and Western blot. FLSCs were induced to differentiation by hepatic growth factor (HGF) and transforming growth factor β (TGF β), respectively, and the ability of dual direction (hepatocyte and cholangiocyte) differentiation was measured by exploring the expression alteration of Albumin (Alb),Results:FLSCs cells were successfully cloned. Stem cell related markers including epithelial cell adhesion molecule (EpCAM), CD133 and CD49f were detected by flow cytometry. The positive expressions of EpCAM, CD133 and CD49f were 78.6%±3.3%, 31.7%±2.5%and 47.6%±1.8%, respectively. The relative mRNA and protein expression  levels of AFP in FLSCs and mature hepatocytes were 0.640±0.115, 0.053±0.012 and 1.383±0.265, 0.243±0.227, there were significant differences in AFP expression between FLSCs and mature hepatocytes (t=8.772, 5.354, P<0.05). FLSCs and mature hepatocytes were both cultured in ultralow attachment dishes for 2 weeks. There was a significant difference in the clone formation rate beteween the FLSCs and mature hepatocytes, which were 234.0±57.0 and 5.0±2.0, respectively (t=12.711, P<0.05). After induced differentiation by HGF in vitro, the expression level of Alb and CK-8 in fetal liver stem cells peaked at the 8th day and the 10th day, which were 0.851±0.030 and 0.771±0.031, respectively. The protein expression levels of Alb and CK-8 in FLSCs peaked at the 10th day, which were 4.573±0.015 and 1.562±0.029, respectively. After the induction of differentiation by TGF-β  in vitro, the mRNA expression levels of CK-7 and CK-19 in FLSCs peaked at the 12th day, which were 15.454±2.152 and 10.675±1.822, respectively. The mRNA expression levels of CK-7 and CK-19 in FLSCs peaked at the 14th day, which were 3.423±0.105 and 1.892±0.081, respectively.EGFP could be detected in both hepatocyte and cholangiocyte after transplanting FLSCs to mouse hepatectomy model.