| Objective To investigate the feasibility of the high - sucrose - high - fat diet and injecting with low dose STZ induced the model of type 2 diabetic rat , and observed the characteristics of blood sugar and blood fat and blood insulin.Methods SD rats(n=32) were randomized into normal control(NC) group(n=10),high-fat diet(HF) group(n=10) and diabete mellitus(DM) group(n=12), HF and DM group rats were fed with the diet enriched with high glucose and high fat, NC group rats were fed with routin animal feeds. The body mass(BM)was measured weekly. At 12 weeks, the blood of three groups rats was gained from its fossa orbitalis to measure triglyceride(TG),cholesterol(TC),fasting peripheral blood glucose(FBG),fasting insulin(FINS), insulin resistance index and insulin sensitivity index were calculated. HOMA-IR=(FBG*FINS)/22.5,ISI=Ln[1/(FBG*FINS)].streptozotocin (STZ,25mg/kg) was administered to the DM group rats via intraperitoneal injecting, once a week for the DM group rats, no more than 2 times, the same volume of axenic citric acid-citrate sodium balanced solution was administered to the NC and HF group rats via intraperitoneal injecting, the rats whose random blood glucose>11.1mol/L were diagnosised type 2 diabetes(T2DM). At 22 weeks all rats were executed, BM,FBG,FINS,TC,TG were measured, insulin resistance index and insulin sensitivity index were calculated.Results⑴At the 12th week:①the BM, level of TG, TC, FINS in HF and DM group were significantly higher than those in the NC group(P<0.01),②level of FBG was no significant difference in three groups(P>0.05),③ISI was degraded slightly in the HF and DM group, but there was no significant difference compared with the NC group(P>0.05); Hyperlipemia and hyperinsulinemia were appeared in HF and DM group, in which HOMER-IR were significantly higher than those in the control group(P<0.01). ⑵At the 22th week:①level of FBG in DM group was significantly higher than those in NC and HF group(P<0.01), but there was no significant difference between in NC and HF group(P>0.05).②Level of FINS in DM group was significantly lower than those in the HF group(P<0.01);but there was no significant difference between in the DM group and NC group(P>0.05).③ISI in HF and DM group was significantly lower than those in NC group(P<0.01), ISI was lower slightly in the DM group than HF group, but there was no significant difference(P>0.05); HOME-IR in HF and DM group was significantly higher than those in NC group(P<0.01),and HOME-IR was significantly higher in the DM group than HF group.④level of TG, TC in HF and DM group were significantly higher than those in the NC group(P<0.01).⑶In the DM group, through treated with STZ, the level of FBG in the 22th week was significantly higher than in the 12th week(before treated with STZ) (t=-5.025,P<0.01); Level of FINS was decreased significantly(t=4.976,P<0.01); HOME-IR was increased significantly(t=-6.192,P<0.01);ISI was slightly decreased, but there was no statistics significance(t=1.914,P>0.05); level of TG and TC were no significant change(t=-1.323,P>0.05;t=-1.786,P>0.05).Conclusion The high - sucrose - high - fat diet and low dose STZ induced the model of T2DM rat, whose metabolism characteristic closely simulates the human T2DM , this study provides an ideal animal model for investigating human T2DM. Objective To observe the effect of pioglitzone on the serum and urine intercellular adhesion molecule-1 (ICAM-1) level, the renal expression of ICAM-1, renal constitution and function and investigate its possible renoprotective mechanisms in type 2 diabetic (T2DM) rats.Method T2DM rats models were established before, SD rats of the model were divided into two groups: diabetes mellitus (group DM, n=10) and diabetic rats treated with pioglitazone(group PIO,n=10) .Each rat in group DM and PIO was fed with the high - sucrose - high - fat diet. Normal control rats (group NC,n=10) were fed with routin animal feeds. The group PIO was treated with pioglitazone (10mg.kg-1.day-1) via intragastric administration, the group DM and NC were treated with corresponding sodium chloride. Body mass (BM) and peripheral blood glucose of each group were tested weekly. The level of serum intercellular adhesion molecule-1(SICAM-1), glycosylated hemoglobin A1c(HbA1c), FBG, FINS, TG, TC as well as urinary albumin/creatinine ratio (ACR), urinary retinol binding-protein (URBP) excretion rate and urinary intercellular adhesion molecule-1(UICAM-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 ICAM-1 protein by histochemical staining.Results1. The levels of FBG and HbA1c at the 8th weeks 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 at 8th week 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. SICAM-1 level ,UICAM-1 excretion rate, ACR , URBP excretion rate and kidney/body weight ratio at the 8th week in groups DM and group PIO increased significantly compared with those in group NC (P<0.01). Treatment with pioglitazone also significantly reduced SICAM-1 level ,UICAM-1 excretion rate, ACR , URBP excretion rate as well as kidney/body weight ratio (P<0.01). In addition, UICAM-1 excretion rate showed positive correlations with ACR (r=0.807, P<0.01), URBP excretion rate (r=0.946, P<0.01) and kidney/body weight ratio (r=0.697,P<0.01) and SICAM-1 level also showed positive correlations with ACR (r=0.790,P<0.01), URBP excretion rate (r=0.823, P<0.01) and kidney/body weight ratio (r=0.566, P<0.01).4. At the 8th week, the expression level of ICAM-1 protein in glomcrulus and nephric tubule in group DM and group PIO was significantly higher than that in group NC, pioglitazone can inhibit the expression of ICAM-1 protein.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 Treatment with pioglitazone can lessen pathological lesion of diabetic nephropathy in T2DM rats, which can definitely protect diabetic nephropathy, such as reduce ACR, URBP excretion rate as well as kidney/body weight ratio. The mechanisms may be associated with decreasing the expression of ICAM-1 protein in renal tissue , reducing SICAM-1 level and the urinary excretion of ICAM-1.
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