Study of protective effect of pachymic acid on obstructive hydronephrosis interstitial fibrosis

Abstract

Objective To investigate protective effects of pachymic acid (PA) on renal interstitial fibrosis induced by hydronephrosis of obstructive models and its potential mechanism.Methods Twentyeight male C57 mice were divided into four groups according to random list method,each containing seven mice.A:sham operation group; B:model group; C:a small dose pachymic acid group; D:a high dose pachymic acid group.All mice were sacrificed on 7 days after operation and tubular injury was observed using hematoxylin and eosin (HE) staining.Sirius red staining was performed to detect the expression of collagen in interstitial,and immunohistochemistry and real-time polymerase chain reaction (Real-time PCR) were used to assay mRNA expressions of collagen-1 (COI-1),fibronectin (FN) and α-smooth muscle actin (α-SMA).Transforming growth factor-β1 (TGF-β1),pSmad2/3,matrix metalloproteinase-9 (MMP-9) at protein levels were measured using Western blotting.Results Seven days after the treatment of pachymic acid in unilateral ureteral obstruction (UUO) model,HE staining indicated that renal tubular injury was ameliorated in the PA treated group,and the results of Sirius red staining showed that renal interstitial fibrosis were significantly reduced compared to model group,and it is more obvious in high dose group.The results of immunohistochemistry indicated that COI-1,FN,α-SMA expressions were significantly increased in model group,and the treatment of pachymic acid significantly inhibited the expressions of COI-1,FN and α-SMA in matrix.Meanwhile,mRNA levels of COI-1 detected by Real-time PCR in model group,the small dose of pachymic acid group and the large dose of pachymic acid group were 4.20 ± 1.42,2.30 ± 0.76,1.70 ± 0.70.Expressions of FN in three groups were 5.20 ± 2.22,3.00 ± 1.70,1.70 ± 1.06 and α-SMA expressions were 4.60 ± 1.23,2.30 ± 0.98,1.40 ± 0.70.There was statistical difference compared with the model group.The results of Western blotting showed pachymic acid could down-regulate expressions of TGF-β1,pSmad2/3 and MMP-9.Conclusion Pachymic acid could improve interstitial fibrosis induced by unilateral hydronephrosis,which might be achieved through the approach of suppressing the expressions of TGF-β1,pSmad2/3 and MMP-9. Key words: Pachymic acid ; Hydronephrosis ; Renal fibrosis ; Matrix metalloproteinase-9