The Effects Of High Salt Diet On Renal Damage And The Intervention Of Telmisartan And Capsaicin In Wistar Rats

Objective: To investigate the effects of high-salt diet on kidney function in Wistar rats andthe interventional impact of Telmisartan and Capsaicin.Methods: Sixrty-five male Wistar rats were randomly divided into control group (NSDgroup: fed with0.5%NaCl), high-salt group (HSD group: fed with4%NaCl), high-salt+telmisartan group (HSD+ARB group: fed with4%NaCl+telmisartan), high salt+capsaicin group (HSD+CAP group: fed with4%NaCl+capsaicin).The tail-cuff arterypressure was determined every two weeks. After rats were fed for24weeks, high-saltgroup was divided into high-salt group with normal blood pressure (HSD-N group) andhigh-salt group with hypertension (HSD-H group) according to the tail artery pressure. HEand MASSON staining were used to detect the renal morphology and fibrosis, respectively.The urine was collected to determine the level of Na+, K+, albumin, retinol-binding protein,Tamm-Horsfall Protein and total protein and creatinine. The activity of Na+-K+-ATPaseand Ca2+-ATPase were assessed by spectrophotography. The techniques ofimmunohistochemistry was used to detect the protein expression of Na+-K+-ATPaseα1，PPARγ，p-NF-κB p65. Real time RT-PCR was performed to measure the mRNAexpressions of Na+-K+-ATPaseα1、PMCA1. Western blotting assay was applied todetermine the protein expression of Na+-K+-ATPaseα1，PPARγ，p-NF-κB p65in renalcortex and medulla nephrica.Results: The blood pressure in HSD-H group was higher than the other groups (P<0.05).HE and Masson staining showed that the kidney in HSD group was more severe interstitialand glomerulus fibrosis and injury compared to NSD group.Compared with NSD, the ratioof Na+to K+, total protein,retinol-binding protein and Tamm-Horsfall Proteinof24hour-urine in high-salt group were increased (P<0.05), creatinine clearance ratedecreased(P<0.05). Compared with HSD group, microalbumin in HSD+ARB group andHSD+CAP group were reduced, creatinine clearance rate increased in HSD+CAP group (P<0.05). The activity of Na+-K+-ATPase and Ca2+-ATPase in HSD group were muchlower than in NSD group(P<0.05),but the mRNA expression of Na+-K+-ATPaseα1andPMCA1were much higher(P<0.05). Compared with NSD group,the protein expression ofPPARγ and p-NF-κ B p65of renal cortex and medulla in HSD group wasincreased(P<0.05).Conclusion:（1）High-salt diet may cause hypertension in part of Wistar rats.（2）High salt-induced kidney injury could be independent of blood pressure.（3）Theinhibition of activity of Na+-K+-ATPase and Ca2+-ATPase and activation of PPARγ andNF-κB p65may be involved in the mechanisms of kidney injury induced by high-saltdiet.（4）Telmisartan could attenuate high-salt-induced kidney function injury via reducingNF-κB p65and increasing PPARγ protein expression.（5）Capsaicin may reduce bloodpressure and alleviate renal damage.