| Renal fibrosis is the final result in the development of most chronic kidney diseases(CKD)characterized by tubulointerstitial fibrosis,tubular atrophy,glomerular sclerosis,renal structural disorders and impaired renal function.Renal fibrosis ultimately leads to renal failure and end-stage renal disease with high morbidity and mortality,which needs requiring dialysis or kidney transplant treatment.It was provided with increasing extracellular matrix protein,decreasing matrix degradation and epithelial-mesenchymal transition when renal fibrosis happens.Transforming growth factor beta(TGF-β)plays an important promoted role in the development of renal fibrosis,which can directly act on mesangial cells and fibroblasts,induce cell proliferation and differentiation,increase the expression of profibrotic molecules such as collagen and fibronectin.Simultaneously,the Wnt/β-catenin signaling pathway plays an important role in renal fibrosis,which induces the expression of target genes and promotes the formation of fibrosis.Objective:To investigate the effects of curcumin(Cur)and bisdemethoxycurcumin(BDMC)on adenine-induced renal fibrosis in rats and to explore the possible mechanisms of TGF-β1 and Wnt/β-catenin signaling pathways.Methods:Seventy-two male Wistar rats were randomly divided into control control group,model control group,Cur high-dose group(200mg/kg),Cur low-dose group(100mg/kg),BDMC high-dose group(200mg/kg),BDMC low-dose group(100mg/kg).Except the control control group,rats were orally administrated with adenine200 mg/kg once a day for 4 weeks,respectively.And the control control group was orally administrated with 0.5% CMC-Na.After 4 hours’ administration of adenine,the rats in each group were orally administrated with the corresponding doses of the test drugs,control control group and model group were respectively given for 0.5%CMC-Na once a day for 4 weeks.At the end of the experiment,24 h urine was collected,blood was taken from the abdominal aorta after the intraperitoneal injection of chloral hydrate,the right kidneys were removed and fixed by 10% formalin and the left kidneys were stored at-80℃.The test indicators are as follows:(1)Weigh the body weight,kidney weight and calculate the kidney index;(2)Measure the contents of 24 h urine protein in rats;(3)Measure the contents of creatinine(Scr)and urea nitrogen(BUN)in serum;(4)Observe the appearance and morphological changes in the kidney,and observe the renal pathological tissues by HE and Masson staining;(5)Investigate the expression of Col I and FN protein in renal tissues by immunohistochemistry;(6)Investigate the expression of TGF-β1,Wnt5 a and β-catenin in renal tissues by western blot.Results:1.Effects on body weight,kidney weight and kidney index in rats Compared with the control group,the body weight in model group rats was significantly reduced(P<0.01).Compared with the model group,the body weight in Cur high-dose group rats and BDMC high-dose group rats increased significantly(P<0.05).Compared with the control group,the kidney weight in model group rats was significantly increased(P<0.01).Compared with the model group,the kidney weight in Cur high-dose group rats and BDMC high-dose group rats was significantly decreased(P<0.05).Compared with the control group,the renal index in model group rats was significantly increased(P<0.01).Compared with the model group,the renal index in Cur high-dose group rats and BDMC high-dose group rats was significantly decreased(P<0.05).2.Effect on the contents of 24 h urine protein in rats Compared with the control control group,the contents of 24 h urine protein in model group was significantly increased(P<0.01).Compared with the model group,the contents of 24 h urine protein in Cur high-dose group and BDMC high-dose group were significantly decreased(P<0.05).3.Effects on Scr and BUN levels in rats Compared with the control group,the contents of Scr in serum in model group were significantly increased(P<0.001).Compared with the model group,the contents of Scr in Cur high-dose group,low-dose group,BDMC high-dose group,low-dose group were significantly reduced(P<0.001).Compared with the control group,the contents of BUN in serum in model group were significantly increased(P<0.001).Compared with the model group,the contents of BUN in Cur high-dose group and BDMC high-dose group,low-dose group were significantly decreased(P<0.01).The contents of Cur low-dose group were significantly decreased(P<0.05).4.Effects on the appearance and histopathology in kidney The kidney appearance in the control group showed control kidney volume,dark red and uniform surface.Compared with the control group,the kidney in model control group became larger,white and the surface of the kidney is uneven which had a granular change.Compared with the model group,the kidney volume of the rats in each administration groups was reduced and the color of the kidney was reddish which the unevenness of the surface was alleviated.The results of HE staining in kidney showed that there was no histopathological change in the control group,and there were control,intact glomerular structure and tubular arrangement under light microscopy.Compared with the control group,there were disordered glomerular structure,obvious fibrosis around the glomerulus,dilated renal tubule,interstitial edema and a large number of inflammatory cell infiltration in model group.Compared with the model group,each administration group rats significantly reduced glomerular contraction,glomerular fibrosis,tubular dilatation,interstitial edema and inflammatory cell infiltration.Masson staining in renal tissue sections showed that only few of collagen fibers were deposited around the glomeruli and renal tubules in the control group.Compared with the control group,there were a large number collagen fibers deposition around the glomeruli and the renal tubules in model group.Compared with the model group,the collagen fiber deposition was significantly reduced around glomerular and tubular tubular in Cur high-dose group,low-dose group and BDMC high-dose group,low-dose group.5.Immunohistochemistry Results The immunohistochemistry results on the expression of Col I showed that the brown staining area in the renal tubular and glomerular in model group was significantly increased compared with the control group.Compared with the model group,the brown staining area was significantly reduced in Cur high-dose group,low-dose group and BDMC high-dose group,low-dose group.The immunohistochemistry results on the expression of FN showed that the brown staining area was significantly increased around the renal tubular and glomerular in model group compared with the control group.Compared with the model group,the area of brown staining was significantly reduced in Cur high-dose group,low-dose group and BDMC high-dose group,low-dose group.6.Western Blot results The expression of TGF-β1 protein in the model group was significantly increased compared with the control group(P<0.001).Compared with the model control group,the expression of TGF-β1 protein was significantly decreased(P<0.001)in Cur high-dose group and BDMC high-dose,low-dose groups.The expression of TGF-β1 protein in Cur low-dose group was significantly decreased(P<0.01).The expression of Wnt5 a protein in the model group was significantly increased compared with the control group(P<0.001).Compared with the model control group,the expression of Wnt5 a protein was significantly decreased(P<0.001,P<0.01)in Cur and BDMC high-dose group.The expression of Wnt5 a protein in Cur and BDMC low-dose group was significantly decreased(P<0.05).The expression of β-catenin protein in the model group was significantly increased compared with the control group(P<0.001).Compared with the model control group,the expression of β-catenin protein was significantly decreased(P<0.001)in Cur high-dose group and BDMC high-dose group,low-dose group.The expression of β-catenin protein in Cur low-dose group was significantly decreased(P<0.01).Conclusions:1.Both Cur and BDMC can improve renal function and histopathological changes in renal fibrosis rats;2.Cur and BDMC can effectively decrease the expression of TGF-β1,Col I and FN proteins,and down-regulated the expression of Wnt5 a and β-catenin proteins in Wnt/β-catenin signaling pathway which could ameliorate renal fibrosis. |
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