Experimental Study On The Effect And Mechanism Of Curcumin On Epithelial-mesenchymal Transition In UUO Rats

Tubulointerstitial Fibrosis is the end-stage of all kinds of kidney disease. Epithelial-mesenchymal Transition (EMT) is one of the important pathogenesis of tubulointerstitial fibrosis.It is characterized by ECM (such as collagenⅠ,Ⅱ,Ⅲ,Ⅳ.fibroncctin and laminin) accumulation and hyperplasia of renal interstitial fibroblasts, leading to changes of normal kidney and loss of kidney function. TGF-β/Smads signal transduction pathway is the main transduction pathway of EMT and plays an important role in EMT. Curcumin is the most important active ingredient of curcuma plants. Curcuma can promot the circulation of qi, dispel wind,activate blood, induce menstruation, relieve pain in traditional Chinese medicine. In recent years, curcumin's antiatheroscloresis, anti-mutation, anti-cancer, antioxidant, scavenging free radicals and other physiological functions have been found. In this study, curcumin was used to intervent EMT and its signal transduction pathway, which has important significance in clarify curcumin's effects and mechanism on tubulointerstitial fibrosis prevention.Objective:In this project, we focus on EMT and its TGF-β/Smads signal transduction pathways to explore the effects and mechanisms of curcumin on tubulointerstitial fibrosis, furthermore, we understand the role of cytokine network in the pathogenesis of EMT, providing new ideas and new methods for better carry out Chinese medicine against renal tubulointerstitial fibrosis.Method:Adult male rats underwent unilateral ureteral obstruction.32 healthy Sprague-Daw ley rats were randomly divided into 4 groups:the sham-operation group, UUO group, curcumin group 1 and curcumin group 2. UUO group were treated with left unilateral ureteral obstruction.2 days after surgery, the rats of curcumin group 1 were intragastrically administrated with curcumin(100 mg/kg/day) and 10 days after surgery, the rats of curcumin group 2 were intragastrically administrated with curcumin(100 mg/kg/day). The sham-operation group and UUO group were intraperitoneally injected with identical volume of normal saline.28 days after surgery,obstructed-kidneys were harvested, and the following indicators were detected.1. Experimental Study on the Effect of Curcumin on Histological Changes in UUO RatsHE staining and Masson staining were used to observe the pathological changes of each group to observe the effects of curcumin on pathological changes in the obstructed kidneys, preliminary discuss the protection of curcumin on tubulointerstitium interstitial fibrosis.2. Experimental Study on the Effect of Curcumin on ECM Expression in UUO RatsTo observe the effects of curcumin on ECM expression in UUO rats and discuss the protection of curcumin on tubulointerstitium interstitial fibrosis deeply. Col-Ⅰ, Col-Ⅲand FN were observed by immunohistochemical method. Col-Ⅰand Col-ⅢmRNA expression were detected by real-time quantitative PCR.3. Experimental Study on the Effect of Curcumin on EMT in UUO ratsa-SMA and E-cadherin were observed by immunohistochemical method to observe the effects of curcumin on EMT in UUO rats.4. Experimental Study on the Effect of Curcumin on TGF-β/Smads signaling pathway in UUO ratsTo observe the effects of curcumin on TGF-β/Smads signaling pathway in UUO rats. TGF-β1,Smad2,Smad3 and Smad7 protein expression were deyected by western blot, TGF-β1,TPRI mRNA expression were detected by real-time quantitative PCR.Result:①In UUO group, renal cortex and medulla became thin, interstitial widening, Inflammatory cells infiltrating serious. Renal artery intimal thickening and luminal narrowing. Regional distribution of fibrosis was spotty. Glomerulus have gathered in serious regional phenomenon. Tubulointerstitium interstitial fibrosis feature was apparented. All the pathological changes above show that the experiment UUO mould were successful.These morphological changes were relieved, tubulointerstitium damage degree and collagen expression were notably reduced after treated with curcumin. The results indicate that curcumin can relieve renal pathological changes in UUO rats and protect the kidney.②Col-Ⅰ,Col-Ⅲand FN expression of UUO group were increased compared with those in Sham group, after treatment with curcumin, Col-Ⅰ, Col-Ⅲand FN expression was decreased compared with those in UUO group. The results indicate that curcumin can inhibit the expression of Col-Ⅰ, Col-Ⅲand FN in renal tissue.curcumin can inhibit or retard the development of tubulointerstitium fibrosis by reduce ECM excessive deposition.③a-SMA expression of UUO group was increased compared with this in Sham group, a-SMA expression was decreased after treatment with curcumin compared with this in UUO group. E-cadherin expression of UUO group was decreased compared with this in Sham group, after treated with curcumin, E-cadherin was markedly increased compared with those in UUO group. The results indicate that curcumin can inhibit or retard the development of EMT.④Smad2, Smad3,TGF-β1,TβRI expression of UUO group were increased compared with those in Sham group,treatment with curcumin could significantly decrease the above indexes compared with those in UUO group.however, Smad7 expression of UUO group was decreased compared with this in Sham group,after treated with curcumin, Smad7 was markedly increased compared with this in UUO group. The results indicate that curcumin can inhibit or retard the occurrence or development of tubulointerstitium fibrosis by prevent EMT, which may be correlated with its inhibition on TGF-β/Smads signal transduction pathway.Conclusion:Pathological process of EMT has happened with tubulointerstitial fibrosis in UUO rats.Curcumin can significantly relieve main renal pathological damage caused by UUO, reduce excessive deposition of ECM, inhibit the EMT process by affect the expression of several cytokines in TGF-β/Smads signal transduction pathway to inhibit or retard the occurrence or development of tubulointerstitium fibrosis.