Triptolide attenuates renal interstitial fibrosis in rats with unilateral ureteral obstruction

Aim: Extracts of Tripterygium wilfordii Hook F. have been used to treat glomerulonephritis for more than 30 years in China. Most of the anti-inflammatory and immunosuppressive activities of these extracts can be attributed to triptolide (Trip). The present study was to investigate the effect of Trip on renal interstitial fibrosis in a model of unilateral ureteral obstruction (UUO). Methods: UUO or sham-operated rats were randomly assigned to receive mycophenolate mofetil (MMF), Trip or vehicle and were killed on days 7 and 14 after UUO or sham operation. Kidney specimens were fixed for immunohistochemistry for myofibroblasts (alpha-smooth muscle actin, alpha-SMA), macrophages (ED-1), monocyte chemoattractant protein-1 (MCP-1) and osteopontin. Interstitial collagen deposition and amounts of transforming growth factor-beta 1 (TGF-beta 1) were determined by Sirius red staining and enzyme-linked immunosorbent assay, respectively. The mRNA expression of TGF-beta 1, connective tissue growth factor (CTGF), MCP-1 and osteopontin were measured by real-time polymerase chain reaction analysis. Results: The scores for the density of alpha-SMA- and ED-1-positive cells, the staining of MCP-1 and osteopontin, interstitial collagen deposition and amounts of TGF-beta 1 were significantly reduced by MMF or Trip. MMF or Trip significantly reduced the mRNA expression of TGF-beta 1, CTGF, MCP-1 and osteopontin. Conclusion: Trip significantly attenuated tubulointerstitial fibrosis in a rat UUO model and the effect of Trip on renal fibrosis was similar to that of MMF. Trip may be useful as a potential candidate in the treatment of renal fibrosis.