Effect Of Pioglitazone On Renal And Nf-κb,mcp-l Expression In Type 2 Diabetic Rats

Objective To observe the effect of pioglitzone (PIO) on monocyte chemoattractant protein-1(MCP-1) and nuclear factor-κB (NF-κB) level, the renal expression of NF-κB and MCP-1, renal constitution and function and investigate its possible renoprotective mechanisms in type 2 diabetic (T2DM) rats.Method The model of T2DM rat was established by fed with high-sucrose-high-fat diet and injected low dose Streptozotocin (STZ) 25mg/Kg, the model of the rats were randomly divided into diabetic (DM group) and pioglitazone (PIO group), compared with the normal control group (NC group) fed with normal diet. Then treated with pioglitazone intervention in PIO group. The group PIO was treated with pioglitazone 10mg/Kg.d via intragastric administration, the group DM and NC were treated with corresponding sodium chloride. The level of serum monocyte chemoattractant protein(SMCP-1), NF-κB, fasting insulin(FINS),triglyceride(TG),cholesterol(TC), fasting peripheral blood glucose(FBG),glycosylated hemoglobin A1c(HbA1c), urinary albumin/creatinine ratio(ACR),urinary retinol binding-protein(URBP),urinary monocyte chemoattractant protein-1(UMCP-1) excretion rate were tested at the 8th week, and the renal tissues of all rats were obtained partly for evaluating kidney/body weight ratio, observing pathologic changes via light microscope and electron microscope, partly for examining the expression of MCP-1,NF-κB protein by histochemical staining.Results1. The levels of FBG and HbA1c in group DM and group PIO were significantly higher compared with those of group NC(P<0.01),and there were no statistical differences between group DM and group PIO (P>0.05);Level of FINS in group PIO was significantly lower than those in the DM group(P<0.05);but there was no significant difference between in the PIO group and NC group(P>0.05). 2. TC and TG level in groups DM and group PIO increased significantly compared with those in group NC (P<0.01).Treatment with pioglitazone significantly reduced the TC and TG (P<0.01).3. NF-κB,SMCP-1 level,UMCP-1 excretion rate,ACR,URBP excretion rate and kidney/body weight ratio in groups DM and group PIO increased significantly compared with those in group NC (P<0.01). Treatment with pioglitazone also significantly reduced NF-κB, SMCP-1 level, UMCP-1 excretion rate, ACR, URBP excretion rate as well as kidney/body weight ratio (P<0.01). In addition, UMCP-1 excretion rate showed positive correlations with ACR, URBP excretion rate and kidney/body weight ratio and NF-κB, SMCP-1 level also showed positive correlations with, URBP excretion rate and kidney/body weight ratio.4. The expression level of MCP-1,NF-κB protein in glomcrulus and nephric tubule in group DM and group PIO was significantly higher (P<0.01)than that in group NC, pioglitazone can inhibit the expression of MCP-1,NF-κB protein(P<0.01).5. The light microscopes results showed that there's no pathological lesion of kidney found in group NC. Pathological changes were much more obvious in group DM. It was clear that the glomerular capillary loops were tumbling, lumens blocked, mesangial region widened, basal lamina thickened, mesenterium base increased, the volume of glomerulus became larger and the cell population increased significantly. It also can be observed that the renal tubule was vacuolization and the renal interstitium wasinfiltrated by lots of lymphocytes and emononuclear macrophages. Pathological changes in group PIO were lighter, it can be observed that glomerular capillary lumen was constrictive slightly and few lymphocyte infiltrated.6. The electron microscopes results showed that the structure and width of glomerular basement membrane (GBM), epithelial foot processes (FP) as well as the mesangial region were normal in group NC at the 8th week. In group DM, the FP fusion rate was approximately 80 percent and the thickening of GBM were observed. it was noted that some FP were destroyed, even vanished, the ultrastructure of GBM became ambiguous, the mesangial cells swelled and the extracellular matrix accumulated which caused mesangial region to expand intensively. After the treatment of pioglitazone, the thickness of GBM in group PIO decreased markedly compared with that in group DM. It was clear that the ultrastructure of GBM was relatively regular, only 30 percent of the epithelial foot processes fused and the expansion of the mesangial region was unconspicuous.Conclusion Local renal inflammatory NF-κB, MCP-1 expression is closely to the occurrence and development of diabetic nephropathy diagnosis and has evaluation of the severity of a certain value. Pioglitazone reduces urinary protein excretion, inhibition of renal interstitial infiltration of inflammatory cells, suggesting that renoprotection. Pioglitazone significantly reduced kidney of local NF-κB, MCP-1 over-expression, lowering blood NF-κB, MCP-1 concentration and urinary MCP-1 excretion, which may pioglitazone has anti-inflammatory effect and show its protective effects on the DN one of the important mechanisms.