OBJECTIVE: To investigate the effects of recombinal human connective tissue growth factor(rhCTGF) stimulation on epithelial-myofibroblast transdifferentiation (EMT) and collagen-synthesis in human renal tubular epithelial cell line(HK2) in vitro. METHODS: The cultured HK2 cells were stimulated with rhCTGF of 5 ng/mL.The morphological changes were observed under an inverted microscope. The cells were collected at 0, 3, 6, 12, 24 and 48 hrs after rhCTGF stimulation. The expression of E-cadherin, α-smooth muscle actin (α-SMA), collagen Iα_1 (Col Iα_1) and collagen IVα_1(Col IVα_1) mRNAs were detected by RT-PCR. RESULTS: rhCTGF stimulation changed the HK2 cell appearance from oval to fusiform, down-regulated the E-cadherin mRNA expression and up-regulated α-SMA mRNA expression, but had no effects the Col Iα_1 and Col IVα_1 mRNA expression. CONCLUSIONS: Exogenous CTGF can mediate the EMT but has no collagen-synthesis effects on HK2 cells.