【作者】 钱燕；

【导师】 李素梅；

【作者基本信息】 安徽医科大学 ， 内科学， 2008， 硕士

【摘要】 目的观察罗格列酮对糖尿病大鼠血细胞间黏附分子-1(serum intercellular adhesion molecule-1, SICAM-1)的水平、尿细胞间黏附分子-1(urinary intercellular adhesion molecule-1, UICAM-1)的排泄以及肾组织ICAM-1 mRNA表达的影响,探讨罗格列酮对糖尿病大鼠的肾脏保护作用及可能存在的机制。方法将24只Wistar大鼠随机分为正常对照(A组)、糖尿病模型组(B组)、罗格列酮治疗组(C组),每组各8只。B、C组单次腹腔注射链脲佐菌素(streptozotocin, STZ)65 mg/kg以建立1型糖尿病大鼠模型。模型建立一周后,C组以罗格列酮(5mg/kg/day)灌胃给药,A组和B组则灌以相应量的生理盐水。每周均监测各组大鼠血糖,第8周时处死大鼠收集各组血、尿及肾脏标本,用于检测大鼠SICAM-1和糖化血红蛋白(glycosylated hemoglobin A1c, HbA1c)水平、12小时尿白蛋白排泄率(urinary albumin excretion rate, UAER)、尿视黄醇结合蛋白(urinary retinol binding-protein, URBP)和UICAM-1的排泄率,留取的肾脏标本部分用于计算肾脏肥大指数、在光镜和电镜下进行病理学检查,部分用于提取RNA,通过逆转录聚合酶链反应(reverse transcriptase-polymerase chain reaction, RT-PCR)以检测肾脏组织ICAM-1 mRNA的水平。结果1.在第2、4、8周,糖尿病组大鼠(包括B组和C组)的血糖水平均明显高于正常对照组(A组)(P<0.01),而B组和C大鼠在各相应时间点的血糖以及第8周的HbA1c值,均无统计学差异(P>0.05)。2.第8周时,B、C组SICAM-1水平和UICAM-1排泄率以及UAER、URBP排泄率和肾脏肥大指数均高于A组(P<0.01);C组上述指标值较B组均明显降低(P<0.01);且SICAM-1和UICAM-1与UAER、URBP排泄率和肾脏肥大指数均呈正相关关系。3.第8周时,光学显微镜下A组肾小球毛细血管腔均匀一致,无狭窄,肾小管-间质无炎症细胞浸润;B组则形态学改变较明显:大鼠肾小球毛细血管袢塌陷,管腔闭塞,系膜区增宽,基膜增厚和系膜基质增多,肾小球体积增大,细胞数量增多,出现玻璃样变;肾小管尤其是近区小管肿胀、变性、空泡形成,肾间质可见大量淋巴细胞和单核巨噬细胞浸润。C组病变较轻,可见肾小球毛细血管管腔轻度狭窄,肾小管-间质见少量淋巴细胞浸润;4.透视电子显微镜下可见第8周时A组肾小球基底膜(glomerular basement membrane, GBM)厚度均匀一致,未见足突(foot processes, FP)融合;B组GBM厚薄不均、结构模糊,FP广泛破坏和融合,其融合率约为80%,系膜区基质增多,系膜区扩大,系膜细胞肿胀。经过罗格列酮治疗后,C组的GBM无明显增厚,GBM的微结构相对规则,有少量FP融合,FP融合率约为20%,系膜区细胞轻度增生。5.第8周时,B、C组大鼠肾脏ICAM-1 mRNA表达较A组均上调(P<0.01),而C组明显低于B组(P<0.01)。结论肾脏组织ICAM-1 mRNA及其蛋白表达的上调可能是DN的发生机制之一;罗格列酮对糖尿病大鼠肾损害具有一定的保护作用,这种作用不依赖其降血糖作用而独立存在,其机制部分可能与其下调体内ICAM-1的表达、降低血、尿ICAM-1的水平有关。更多还原

【Abstract】 Objective To observe the effect of rosiglitazone on the serum intercellular adhesion molecule-1 (SICAM-1) level, urinary excretion of ICAM-1 and renal expression of ICAM-1, and investigate its possible renoprotective mechanisms in diabetic rats.Method 24 Wistar Rats were divided into three groups: non-diabetic control rats (group A, n=8), streptozotocin-induced diabetic rats (group B, n=8) and diabetic rats treated with rosiglitazone (group C, n=8). Each rat in groups B and C received an intraperitoneal injection of Streptozotocin (STZ) to establish type 1 diabetic models. Rats in group C were treated with rosiglitazone (5mg.kg-1.day-1). One week after the establishment of diabetic model, group A and B were treated with corresponding sodium chloride. Peripheral blood glucose was tested weekly. Glycosylated hemoglobin A1c(HbA1c) and SICAM-1 level as well as urinary albumin excretion rate (UAER), 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 mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR).Results1. The blood glucose levels at the 2nd, 4th, 8th weeks and HbA1c level at the 8th week in group B and group C were significantly higher compared with those of group A (P<0.01), and there’s no statistical differences between groups B and C(P>0.05), including both of the blood glucose and HbA1c levels.2. UAER, URBP excretion rate, UICAM-1 excretion rate, SICAM-1 level and kidney/body weight ratio at the 8th week in groups B and C increased significantly compared with those in group A (P<0.01). Treatment with rosiglitazone significantly reduced the SICAM-1 level and urinary excretion rate of ICAM-1 as well as kidney/body weight ratio and urinary excretion rates of ALB, RBP (P<0.01). In addition, SICAM-1 level showed positive correlations with UAER (r=0.882, P<0.01), URBP excretion rate (r=0.884, P<0.01) and kidney/body weight ratio (r=0.920, P<0.01) and UICAM-1 excretion rate also showed positive correlations with UAER (r=0.907, P<0.01), URBP excretion rate (r=0.900, P<0.01) and kidney/body weight ratio (r=0.950, P<0.01).3. The light microscopes results showed that there’s no pathological lesion found in group A. Pathological changes were much more obvious in group B. 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 was infiltrated by lots of lymphocytes and emononuclear macrophages. Pathological changes in group C were lighter, it can be observed that glomerular capillary lumen was constrictive slightly and few lymphocyte infiltrated.4. 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 A at the 8th week. In group B, however, the FP fusion rate was approximately 80 percent and the thickening of GBM were observed. In addition, 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 rosiglitazone, the thickness of GBM in group C decreased markedly compared with that in group B. It was clear that the ultrastructure of GBM was relatively regular, only 20 percent of the epithelial foot processes fused and the expansion of the mesangial region was unconspicuous.5. Compared with group A, the expression of ICAM-1 mRNA was markedly up-regulated in group B and group C (P<0.01), and rosiglitazone could decrease the expression of ICAM-1 mRNA in the renal tissue (P<0.01).Conclusion The overexpression of ICAM-1 protein and mRNA in renal tissue of diabetic rats may be one of the mechanisms of diabetic nephropathy. Rosiglitazone definitely protect against the renal injury of diabetic rats, which may be partly associated with decreasing the expression of ICAM-1 in the renal tissue, reducing SICAM-1 level and the urinary excretion of ICAM-1, independently of its hypoglycemic effect.更多还原