Effects Of Tranilast On PDGF-D,PDGFR-β Expression And P38MAPK Signaling Pathway In UUO Rat Kidney

Objective:Study of Tranilast（TNL）for unilateral ureteral obstruction（UUO）rats of effect with platelet growth factor D（PDGF-D）and platelet growth factor receptor beta（PDGFR-β）of expression and the p38 mitogen-activated protein kinase（p38MAPK）signaling pathway,explore its possible anti-renal fibrosis mechanism,Provide new experimental theoretical basis and ideas for the treatment of renal interstitial fibrosis（RIF）.Methods:（1）72 male Wistar rats weighing approximately（120-150 g,6 weeks old）were randomly divided into model group（UUO group,24）,tranilast treatment group（TNL group,24）,sham operation group.（Sham group,24）.Left ureteral ligation in rats of UUO group and TNL group to making a renal inte rstitial fibrosis model,Sham group only free left ureter,no ligation,then suture.TNL group was given Tranilast 1 day before surgery,the dose is 150 mg·kg-¹·d^-1[1],dissolved in a 0.5%concentration in 0.5%carboxymethylcellulose solutio n to prepare a suspension for 14 days.（2）On days 3,7,and 14 after surgery,8rats from 3 groups were sacrificed.Remove left kidney tissue,neutral formaldeh yde solution,routine dehydration,paraffin embedding and sectioning,separately HE staining,Masson staining and immunohistochemical detection of PDGF-D protein,PDGFR-βprotein and p-p38MAPK protein（phosphorylation product of p38MAPK protein）.Data were analyzed using SPSS23.0 statistical software,and quantitative data were expressed as mean standard deviation（±S）,one-way ANOVA was used to compare the mean of multiple groups,the LSD-t test was used to compare the mean of the multiple groups,the difference was statistically significant（P<0.05）.Results:1.HE staining results:On the third day after operation in the U UO group,renal tubular injury began to appear in the renal tissue of rats,as th e obstruction time prolongs,the renal tubules expand progressively and the infl ammatory cell infiltration increases,so1me tubules atrophy and destruction,and the tubulointerstitial injury score（TIS）gradually increased,the difference was st atistically significant（P<0.05）.There is no obvious pathological change in renal tissue of Sham group,compared with the time points corresponding to the Sha m group,the TIS of the UUO group increased,the difference was statistically significant（P<0.05）;compared with the time points corresponding to the UUO group,the TNL group had less tubular damage and TIS decreased,and the difference was statistically significant（P<0.05）.2.Masson staining results:In the UUO group,the renal interstitial collagen fibers began to increase on the third day after surgery,with the prolongation of obstruction time,the deposition area of renal interstitial collagen fibers increased,and the fibrous tissue with diffuse hyperplasia appeared.The ratio of renal interstitial fibrosis area（RIF index）increased gradually,and the difference was statistically significant（P<0.05）.The Sham group had a small green staining area of renal interstitial collagen fibers and no renal interstitial fibrosis,compared with the time points corresponding to the Sham group,the RIF index of the UUO group increased,and the difference was statistically significant（P<0.05）.Compared with the time points corresponding to the UUO group,the degree of interstitial fibrosis was reduced in the TNL group,and the RIF index was decreased,the difference was statistically significant（P<0.05）.3.Immunohistochemical results:（1）Immunohistochemistry showed that PDGF-D and PDGFR-βprotein expression sites were mainly located in renaltubu lar epithelial cells.With the prolongation of obstruction time,the expression of PDGF-D and PDGFR-βprotein in renal tissue of UUO group increased gradually,and the difference was statistically significant at each time point（P<0.05）;compared with the time points corresponding to the Sham group,the expressi on of PDGF-D and PDGFR-βprotein in the UUO group increased,the differe nce was statistically significant（P<0.05）;compared with the time points corresp onding to the UUO group,the expression of PDGF-D and PDGFR-βprotein in the TNL group decreased,the difference was statistically significant（P<0.05）.（2）Immunohistochemistry showed that the p-p38MAPK protein expression site was mainly located in renal tubular epithelial cells.With the prolongation of obstruction time,the expression of p-p38MAPK protein in UUO group increased gradually,and the difference was statistically significant at each time point（P<0.05）;compared with the time points corresponding to the Sham group,the expression of p-p38MAPK protein in the UUO group increased,and the differenc e was statistically significant（P<0.05）;compared with the time points correspon ding to the UUO group,the expression of p-p38MAPK protein in the TNL group decreased,and the difference was statistically significant（P<0.05）.Conclusion:1.In the renal interstitial fibrosis of UUO rats,the expression of PDGF-D,PDGFR-βand p-p38MAPK protein increased,suggested that PDG F-D,PDGFR-βand p38MAPK signaling pathways are involved in the process of renal interstitial fibrosis.2.PDGF-D,PDGFR-βand p-p38MAPK protein expression decreased after treatment with Tranilast,indicated that in renal fibrosis,Tranilast inhibits the secretion of PDGF-D and down-regulates the expression of PDGFR-β,in turn,it reduces the activation of p38MAPK phosphorylation in the downstream signaling pathway of PDGFR-β,decreases the expression of p-p38MAPK prot ein,and reduces renal fibrosis.To provide a theoretical basis for further revea ling the pathogenesis of renal interstitial fibrosis and the treatment of renal fibrosis.