[Effect of insulin-like growth factor I on the transdifferentiation and collagen synthesis of human renal tubular epithelial cells].

Aim: To investigate the role of insulin-like growth factor I(IGF-I) in transdifferentiation and collagen synthesis of human renal tubular epithelial cell line HK2 in vitro.

Methods: Cultured HK2 cells were divided into two groups: (1) control group; (2) IGF-I-treated group(25, 50, 100, 200 microg/L, respectively). The cell morphological changes were traced with inverted microscope, and the expression of alpha-smooth muscle actin (alpha-SMA), collagen I alpha and collagen III alpha mRNA was detected by RT-PCR. Concentration of collagen I secreted into the culture supernatant was determined by ELISA.

Results: In HK2 cells, IGF-I stimulated the morphological oval-to-fusiform transdifferentiation of the cells, and upregulated alpha-SMA, collagen I alpha and collagen III alpha mRNA expression(P<0.05). Secreted collagen I level was also up-regulate by IGF-I in the concentration of 100 and 200 microg/L, respectively.

Conclusion: IGF-I can promote the transdifferentiation of human renal tubular epithelial cells and stimulate the synthesis of collagen.