Effects of exogenous connective tissue growth factor on transdifferentiation and extracellular matrix synthesis of human renal tubular epithelial cells

AIM: To investigate the role of exogenous connective tissue growth factor(CTGF) in transdifferentiation and extracellular matrix(ECM) synthesis of human renal tubular epithelial cell line HK2 in vitro. METHODS: Cultured HK2 cells were divided into 3 groups: control group, low dose CTGF-treated group (2.5 μg/L)and high dose CTGF-treated group(20 μg/L) . The cell morphological changes were observed with inverted microscope; MTT assay was used to detect the CTGF effects on cell proliferation; the expressions of E-cadherin,α-smooth muscle actin ( α-SMA), fibronectin(FN) and collagen typeⅠαmRNA were detected by RT-PCR; immunohistochemical staining was used to assess the levels of intracellular FN and collagen typeⅠprotein. RESULTS: In HK2 cells, CTGF stimulated the morphological changes (oval-to-fusiform ), increased the cell proliferative activity. Different concentrations of CTGF downregulated E-cadherin mRNA expression(P0.05), upregulated α-SMA and FN mRNA expressions(P0.05). High concentration of CTGF upregulated collagen typeⅠαmRNA expression(P0.05).The protein expression of FN was increased by the low concentration of CTGF(P0.05). High concentration of CTGF increased the protein expressions of FN and collagen typeⅠ(P0.05). CONCLUSION: CTGF can promote the transdifferentiation of human renal tubular epithelial cells and stimulate the synthesis of FN in vitro. High concentration of CTGF increases the expression of collagen typeⅠprotein.