Roles Of TNF-α And Nuclear Factor-κB In Apoptosis Of Renal Cells In Diabetic Rats

BackgroundIn recent years, with the insulin applying to clinical treatment, the mortality of diabetes of acute complication is obviously reduced. But the chronic complication of Diabetes become the main reason of diabetics'death and disabled, among them the diabetic nephropathy (DN) is one of the main reasons.Cells wither and die are discovered to be an important role in diabetic nephropathy in recent years.No matter vivo experimentation or outside the body,the increased cells wither or die were proved high candy state kidney,but the mechanism is not so obvious in the body.There have been many expirements and clinical data indicate that diabetes usually appears with inflammatory cyto-kines,so inflammatory maybe plays a key role in the pathogenesis ofdiabetic nephropathy as the downstream of the mechanism men-tioned above.NF-κB is an important factor to adjust inflammatory,TNF-a is not only an important inflammatory factor in our body,but also an important activating factor of NF-KB,but we are still not know clearly about whether they take part in Apoptosis or whether down-regulating NF-κB and TNF-a expression can and reducing the number of renal tissue apoptotic cells.Rapamycin is a kind of new immunosupp-ression which is good, low toxicity and non-renal toxicity.Rercent research indicates Rapamycin can inhibit the activation of NF-κB and then inhibit the expression of some some cytokines (such as TNF-a) and Chemokines,thereby shows anti-inflammatory effect.But there's no documents records the activation of NF-κB can be inhibited by Rapamycin and reducing the number of renal tissue apoptotic cells,so our research try to use the ack-nowledged type II diabetic model to look-into the relationship of TNF-a,NF-κB in diabetic renal tissue and the expression of them and renal tissue apoptotic cells and the intervention effect of rapamycin,and discuss the effect of NF-κB and TNF-a in promoting apoptosis and the possible protection mechanism of Rapamycin, so then provide a kind of potential remedy to delay and cure diabetic nephropathy.ObjectiveTo observe the changes in the expression of renal tissue TNF-a, NF-κB and the interrelation to renal cell apoptosis, and their influences of Rapamycin in Diabetie nephropathy.MethodsTen male Wistar rats and ten male GK rats were randomly divided into three groups:normal control (group NC, n= 10), diabetic nephropathy (group DM, n= 10) and diabetic nephropathy treated with Rapamycin(6mg/kg bodyweight,three times a week,group DMR,n=10).The renal cell apoptosis was measured by the method of terminal-deoxynucleotidyl transferase mediated d-UTP nick and labeling (TUNEL). The expression of TNF-a and NF-κB in renal tissue were examined by immunohistochemistry. The interrelation between TNF-αand NF-κB were analyzed by Pearso method, and the interrelation between TNF-a, NF-κB and renal tissue apoptotic cells was analyzed by Spearman method.Results(1) Changes in blood glucose, blood cholesterol and blood triglyceride in the 3 groups of rats (Tab 1):Comparison of blood glucose:diabetic group>Rapamycin treatment group>normal group.There were no differences in serum cholesterol and triglyceride among three groups.(2) The Comparison of urine protein and pathological changes of glomeruli of kidneyin the 3 groups of rats:The urine protein and pathological changes of glomeruli of kidneyin was significantly lower in rapamycin-treated group as compared with diabetic group (p<0.05).(3) The number of renal tissue apoptotic cells was increased progressively from 4w to 8w diabetic rats (P<0.01).(4) Immunohistochemistry staining showed that the positive expression of renal tissue TNF-a and NF-κB were increased progressively from 4w to 8w diabetic rats compared with control group (all P<0.01).(5) The expression of TNF-a was positively correldted with NF-κB (r=0.956, P<0.01).(6) The expression of renal cell apoptosis was also positively correlated with TNF-a and NF-KB(r=0.953, r=0.886, P<0.01) in diabetic rats.(7)The expression of renal tissue TNF-a(P<0.01)as well as the expression of NF-κB(P<0.01)in the Rapamycin therapy group were much lower than that in the diabetic group.Conclusions(1) Rapamycin could decrease serum glucose levels and improve the urine protein and pathological changes of glomeruli of kidneyin in GK rats.(2) The number of renal tissue apoptotic cells was increased progressively partly because of the mechanism of apoptotic cells.(3) NF-κB and TNF-a are playing an important role in diabetic nephropathy.(4) Rapamycin has some renal protective effect on diabetes in rats, partly through down-regulating NF-κB and TNF-a expression and reducing the number of renal tissue apoptotic cells.