波生坦对糖尿病大鼠的肾脏保护作用

RENOPROTECTIVE EFFECTS OF ENDOTHELIN RECEPTOR ANTAGONIST BOSENTAN ON DIABETIC RATS

目的 :观察非选择性内皮素受体拮抗剂波生坦 (Bosentan)对糖尿病SD大鼠的肾脏保护作用。 方法 :设糖尿病非治疗组 (DM组 )、糖尿病Bosentan治疗组 (DM B组 )及正常对照组 (SD组 ) ,每组 6只大鼠。予SD大鼠一次性腹腔注射链脲佐菌素 6 5mg/kg ,诱导建立糖尿病模型。在DM B组中 ,予大鼠Bosentan 10 0mg/ (kg·d)灌胃 ,持续 4周。 4周后观察各组大鼠体重、肾重、平均动脉压、2 4h尿蛋白、肌酐清除率 (Ccr)等生化指标 ,比较各组大鼠血循环及肾脏内皮素含量 ,以及采用Westernblot方法观察各组大鼠肾脏转化生长因子β1(TGF β1)的表达 ,并用免疫组织化学方法观察肾脏细胞外基质Ⅳ型胶原、Laminin以及TGF β1表达。 结果 :DM组大鼠 2 4h尿蛋白排出量、Ccr与SD大鼠对照组相比均明显增加 (均为P <0 0 0 1)。Bosentan使糖尿病大鼠的尿蛋白与Ccr正常化 (与正常组相比 ,均为P >0 0 5 )。Westernblot结果显示肾脏TGF β1蛋白水平在DM组大鼠明显升高 (P <0 0 1) ,为SD组大鼠的 1 97倍 ,Bosentan可使其抑制 5 3 5 % ,与DM组差别有极显著意义 (P <0 0 1)。免疫组织化学结果表明 ,在DM组大鼠中 ,肾小球、肾小管基膜及肾小球系膜区Ⅳ型胶原与Laminin的表达明显增加 ,肾小管间质的TGF β1表达也显著增加。Bosentan?

To investigate the effects of endothelin receptor antagonist bosentan on the progression of renal injury in diabetic SD rat. METHODOLOGY 18 male SD rats(150～180g,8 weeks old)were included in the study.They were divided into 3 groups at random:untreated diabetic group(DM group, n =6),bosentan treated diabetic group(DM-B group, n =6)and normal control group (SD group, n =6).Diabetic rats were induced by intraperitoneal Streptozotocin injection(65 mg/kg)at one dose,and then divided into DM group and DM-B group.The DM-B group was given Bosentan 100 mg/(kg·d) by gavage for 4 weeks, while the DM and SD groups were given sterile water only.At the end of the fourth week,all rats fasted for 16 hours and 24 hours urine samples were collected.Under anestheization with 3% intraperitoneal chloral hydrate,a polyethylene(PE-50)catheter was applied to measure,mean arterial pressure(MAP)and to sample arterial blood at the rat′s right common carotid artery.Body weight,kidney weight,urinary protein excretion,creatinine clearance,circulating and renal endothelin were detected.Furthermore,the protein expression of renal matrix components,type Ⅳ collagen and laminin,as well as that of transforming growth factor β 1(TGF-β 1)were determined by immunohistochemistry and Western blot analysis. RESULTS Untreated diabetic rats(DM group)had enhanced urinary protein excretion(68 2±0 34 mg/24h)and creatinine clearance(1 38±0 35ml/min)than those in normal group(14 68±2 01mg/24h,0 74±0 11ml/min, P <0 001,respectively).In DM group,immuno-histochemistry analysis showed over-expression of type Ⅳ collagen,laminin and TGF-β1.The change of TGF-β1 was further determined by Western blot method(1 97-folds higher than normal ones, P <0 01).Bosentan not only normalized urinary protein(28 2±3 60 mg/24h, P >0 05 vs .normal control)and creatinine clearance(1 13±0 31ml/min, P >0 05 vs .normal control),but also decreased the type Ⅳ collagen and laminin accumulation in the kidney.The expression of TGF-β1 in the kidney was significantly inhibited by 53 5% at the same time( P <0 01 vs. untreated diabetic rats). CONCLUSION Bosentan improves renal function by decreasing the extracellular matrix accumulation and TGF-β1 expression in kidney in diabetic rat,thus provide a new therapeutic approach to diabetic nephropathy.