Celecoxib Connective Tissue Growth Factor-induced Renal Tubular Epithelial Cell Transdifferentiation

BackgroundTubulointerstitial fibrosis is thought to be the final common pathway leading to end-stage renal disease. Myofiroblast has been found to play an important role in the progression of renal interstitial fibrosis.. tubular epithelial-myofibroblast transdifferentiation (TMET) may play an important role in the pathogenesis of renal interstitial fibrosis. The characteristic protein of myofibroblast is namedα-smooth muscle actin (α-SMA).Previous study had showed that CTGF can induce TMET. so it may be another way to block fibrosis. In this study we examed the capacity of celecoxib to inhibit the transdifferentiation of tubular epithelial cells to the myofibroblastic phenotype and hence reduce the production of collgen.MethodsCultured HK-2 cells were divided into control group, celecoxib with different doses treated group, CTGF with different doses treated group ,10ng/ml CTGF and celecoxib with different doses treated group. The morphology of transdiffferentiate tubular cells was observed under phase-contrast microscopy. The expression of the mesenchymal markerα-smooth muscle actin were shown by indirect immunofluorescence assay. Flowcytometry was used to assess the percentage ofα-SMA positive cells and mean channel fluorescence (MCF).The level of PGE2 in the culture supernatant was measured by ELISA. The protein expression ofα-SMA was detected by western blotting.Results①There was mo difference between celecoxib treated alone and the control (P >0.05) .②CTGF caused transdifferentiation of HK-2 cells into myofibroblast-like cells and showed strongα-SMA immunofluorescence. The percentage ofα-SMA positive cells and MCF were more than that of normal control group (P<0.05). The level of PGE2 in the culture supernatant was alsoincreased (P<0.05).③With the presence of CTGF and celecoxib, the HK-2cells morphology transdifferentiation were inhibited. And with celecoxib, there are decrease trend of the percentage ofα-SMA positive cells, the amount of PGE2 and the expression ofα-SMA (P<0.05) .ConclusionCTGF could induced TEMT and increased the level of PGE2 in culture supernatant, celecoxib blocked TEMT. It could also reduce the level of PGE2 in culture supernatant. It maybe indicates that celecoxib inhibits TEMT by the action of reducing the expression of CTGF.