Effect Of Stem Cell Factor On Phenotypic Changes And TGF-β 1 Expression In Human Renal Tubular Epithelial Cells

Objective To investigate the effects of stem cell factor（SCF）on phenotypic change and the expression of TGF-β₁ and fibronectinin human renal tubular epithelial cells line（HK-2）in vitro,andtoclarifytheimpactof SCFon developmentand progressionofrenal fibrosis.Methods HK-2 cells cultured in vitro were divided into four groups by SCF concentrations: control,10 ng/mL,50 ng/mL,100 ng/mL.The HK-2 cells were divided into five groups according to the stimulation time of 50 ng/mL SCF: control,6 hours,12 hours,24 hours,48 hours.The morphology of HK-2 cells was detected by the inverted phase contrast microscope.The expression of α-Smooth muscle actin（α-SMA）,transforming growth factor beta 1（TGF-β₁）and fibronectin at both m RNA and protein levels was detected by Real-time PCR and Western blot,while the supernatant level of TGF-β₁ was measured by ELISA.Results（1）With the increase of the concentration and the extending of stimulation time of SCF,HK-2 cells were graduallystretched for spindle shape from roundor round-like shape.（2）Real-time PCR and Western blot showed that the expressions of α-SMA,TGF-β₁ and fibronectin at both m RNA and protein levels were increased in HK-2 cells treated with SCF（10 ng/mL,50 ng/mL,100 ng/mL）compared with the control group.With the concentration of SCF increased,the expressions of α-SMA,TGF-β₁ and fibronectin were gradually increased（P < 0.05）.And the expressions of α-SMA,TGF-β₁ and fibronectin in HK-2 cells treated with SCF（the concentration was 50 ng/mL）for different stimulation time were gradually increased compared with controlgroup.Compared with the control group,the expressions of these factors were slightly up-regulated after 6 hours（all P > 0.05）,significantly up-regulated after 12 hours（all P < 0.05）,and reached peak after 24 hours（all P < 0.01）,no further increased after 48 hours.（3）ELISA revealed that the secretion of TGF-β₁ in supernatant was roughly synchronized with the expression of intracellular TGF-β₁in a concentration-and time-dependent manner（P < 0.05）.Conclusion SCF can promote the transdifferentiation of HK-2 cells into myofibroblasts and induce the expressions of TGF-β₁ and fibronectin in HK-2 cells in vitro.