The Role Of TGF-β/Smads Signaling Pathway In Curcumin Improving Myocardial Fibrosis In Diabetic Rats

Objective:The main purpose of this study is to observe the changes of collagen and the expression of TGF-beta/Smads signaling molecules in diabetic rat and cell modele under curcumin intervention.To investigate the effects of TGF-β/Smads signaling pathway on the improvement of myocardial fibrosis in the heart of experiment diabetes mellitus by curcumin intervention.Methods:Experimental typeⅡdiabetes was induced in rats by injection of low dose of streptozotocin（STZ）35 mg·kg^-1 combined with high glucose and high fat diet,curcumin(300 mg·kg^-1·d^-1)was orally administered in the drinking water for 16 weeks;The expression of myocardial collagen in rats were detected by sirius red staining and masson staining;The expression of CollagenⅠand CollagenⅢin myocardium of rats were detected by immunofluorescence and Western Blot.Isolating and culturing rat myocardial fibroblast cells,Stimulated cardiac fibroblasts（CFs）in neonatal rats by different concentration of glucose(5.5,20,25,30,35,50 mmol·L^-1)for 24 h to determine the optimum concentration of high glucose model,and high glucose stimulated rat cardiac fibroblasts for 24 h by 30 mmol·L^-1 high glucose plus different concentrations of curcumin(10,25,50,100,200μmol·L^-1)to determine the optimal concentration of curcumin;The expressions of typeⅠandⅢcollagen,TGF-β1,p-Smad2,Smad2,p-Smad3,Smad3 and TβR-Ⅰ、TβR-Ⅱ、TβR-Ⅲin CFs were detected by Western blot.Results:Sirius scarlet staining and Masson staining showed:compared with the control rats,the collagen deposition in the myocardium of the diabetic rats were more obvious and the expression of CollagenⅠand CollagenⅢwere significantly increased.After treatment of curcumin,the collagen deposition in the myocardium and the expression of CollagenⅠand CollagenⅢof diabetic rats were remarkably decreased.Isolating and culturing rat myocardial fibroblast cells,Stimulated cardiac fibroblasts（CFs）in neonatal rats by different concentration of glucose(5.5,20,25,30,35,50 mmol·L^-1)for 24 h to determine the optimum concentration of high glucose model,and high glucose stimulated rat cardiac fibroblasts for 24 h by 30 mmol·L^-1 high glucose plus different concentrations of curcumin(10,25,50,100,200μmol·L^-1)to determine the optimal concentration of curcumin;The expressions of typeⅠandⅢcollagen,TGF-β1,p-Smad2,Smad2,p-Smad3,Smad3 and TβR-Ⅰ、TβR-Ⅱ、TβR-Ⅲin CFs were detected by Western blot.Conclusion:Curcumin administration significantly suppressed the deposition of type I and type III collagens in the heart tissues of diabetic rats and increased risk of myocardial fibrosis in diabetic rats.Curcumin could ameliorat myocardial fibrosis in diabetic rats through TGF-β/Smads signaling pathway and has protective effect on myocardium in diabetic rats.