Abstract: Objective Hepatic progenitor cells(WB-F344) can be differentiated into hepatocytes or cholangiocytes depending on different stimulations. The aim of the current study was to compare influences of exogenous and endogenous connective tissue growth factor(CTGF) on WB-F344 cells differentiation.Methods MTT assay was used to detect cell viability after recombinant human CTGF stimulated WB-F344 cells in complete medium for 24 hours. Western blotting was used to detect CTGF influence on WB-F344 cells differentiation: including the changes of αfetoprotein(AFP), albumin and cytokeratin-19(CK-19). The plasmid expressing CTGF(dl6-95-CTGF) was constructed through inserting the full length of CTGF gene into the AAV vector dl6-95. The stable transfected WB-F344 cells with dl6-95-CTGF using G418 selection. Western blotting was also used to detect the changes of hepatic progenitor markers. Results Twenty-four hours after stimulating WB-F344 by recombinant human CTGF, the viability of WB-F344 was slightly inhibited(P<0.05) without dosedependent manner. High dose(100 ng/mL) of CTGF could change the phenotype markers of WB-F344 cells at protein level: the expression of fetal hepatocyte marker(AFP) was down-regulated, while the expression of mature hepatocyte marker(albumin) and cholangiocyte marker(CK-19) were up-regulated. The plasmid expressing CTGF(dl6-95-CTGF) was constructed and G418 resistant clones were screened for cell clones with stable transfection successfully. Compared with transfected with dl6-95, WB-F344 cells transfected with dl6-95-CTGF could decrease the expressions of AFP and CK-19, while the expression of albumin increased(P<0.05), the results were consistent with CTGF directly stimulated, but the degree of induction was less obvious than that of exogenous CTGF. Conclusion Compared with endogenous CTGF, exogenous CTGF was able to stimulate WB-F344 cells differentiation toward hepatocytes more obviously.

Key words: connective tissue growth factor, hepatic progenitor cells, liver regeneration, differentiation