Effects Of Carnosine On Oxidative Stress And NF-κB Signaling Pathway In Diabetic Nephropathy Rats

ObjectiveBy studying carnosine effects on the oxidative stress and NF-κB signaling pathway response induced by diabetes in rat kidney tissues,to investigate the protective effect of carnosine on the nephropathy of type 2 diabetic rats and its mechanism.MethodsSixty SD male rats of 8-week-old,except for the control group(n=10),were given high fat and sugar diet,and intraperitioneal injection of STZ to establish diabetes rats.After successful modeling,diabetic rats were randomly divided into DN group,low-dose carnosine group,medium-dose carnosine group,and high-dose carnosine group.The carnosine group was intragastrically administered with 100,300,and 900 mg/kg carnosine once a day.After 8 weeks of carnosine administration.Weigh the rat weight and fasting blood glucose(FBG)with a blood glucose meter.Renal function indexes such as micro-urinary albumin(m Alb),serum creatinine(Scr)and urea nitrogen(BUN)detected by automatic biochemical analyzer in 24 hours.HE staining method was used to observe the pathological and morphological changes of the kidney.PAS staining was used to detect the content of reducing sugar in the glomerularbasement membrane.The kit method is used to detect the activity of superoxide dismutase(SOD),malondialdehyde(MDA),glutathione(GSH),glutathione peroxidase(GSH-Px)in kidney tissues that affect the degree of oxidative stress content.Immunohistochemical method to detect the phosphorylation level of NF-κB.Western blot detection of p-NF-κB P65 protein expression in renal tissue.Results1.The test results of rat body weight and fasting blood glucose(FBG)showed that compared with the Con group,the body weight and fasting blood glucose(FBG)of the DN group increased(P <0.01).After carnosine treatment,the body weight decreased to varying degrees.The dose of 300 and 900 mg /kg carnosine in the oral group decreased significantly(P <0.05),fasting blood glucose did not change significantly.2.The test results of renal function indexes showed that m Alb,Scr,BUN and other indexes all improved after carnosine treatment compared with DN group,and showed a dose-effect dependence relationship(P <0.05 or P <0.01).3.The results of pathological morphological staining experiments showed that compared with DN group,HE staining after carnosine treatment.kidney damage was reduced,glomerular volume became smaller,and tubule swelling was reduced.PAS staining after carnosine treatment: basement membrane reducing sugar content Reduced,the glomerular basement membrane and returned to normal levels.4.The oxidative stress index test results showed that compared with the Con group,the MDA content of the DN group increased,the SOD activity,GSH,and GSH-Px protein content decreased(P <0.01).compared with the DN group,the MDA content of carnosine treatment decreased,SOD activity increased,GSH,GSH-Px content increased,with the increase in carnosine dose,the carnosine high-dose group index changes the most obvious(P <0.05 or P<0.01)5.Immunohistochemical results showed that compared with DN group,carnosine can inhibit NF-κB protein phosphorylation,carnosine 900 mg / kg group had the most obvious inhibitory effect.6.Western blot detection of protein expression showed that carnosine can significantly down-regulate p-NF-κB protein expression level(P <0.05 or P<0.01),and the protein expression level decreased sequentially with the increase of the administration concentration.ConclusionsDiabetes can cause diabetic kidney damage,manifested as mesangial cell proliferation,renal tubular endothelial cell swelling,and basement membrane thickening and other pathomorphological changes.The body’s elevated blood glucose,urine protein,and urea nitrogen can reflect changes in renal function indicators of diabetes.Different doses of carnosine can improve the renal function of rats by reducing serum creatinine,urea nitrogen and urinary protein,alleviate the morphological changes of renal tissue,and protect the diabetic nephropathy.The mechanism of action may be related to the carnosine’s antioxidant activity.By inhibiting oxidative stress,it further inhibits the activation of the NF-κB signaling pathway and reduces the level of phosphorylation.So as to protect the kidneys of diabetic nephropathy rats.