肾病幼鼠肾组织尿激酶型纤溶酶原激活物及其抑制物mRNA与蛋白表达的特点和ACEI干预的影响

Protein and mRNA expressions of urokinase-type plasminogen activator and type-1 plasminogen activator inhibitor in renal tissues of nephrotic young rats and interfering effects of angiotensin converting enzyme inhibitor

目的 探讨肾病幼年大鼠肾组织尿激酶型纤溶酶原激活物 (uPA)及其特异性抑制物(PAI 1)mRNA与蛋白质表达的特点 ,及予血管紧张素转换酶抑制剂 (ACEI)苯那普利治疗的影响。方法 采用阿霉素诱导的肾病大鼠为动物模型 ,予ACEI治疗 12周后测大鼠体重、血压、尿蛋白及血生化各项指标的变化 ,同时用Northern杂交及免疫组化染色等方法 ,检测肾组织uPA和PAI 1的mRNA及蛋白表达情况 ,并比较各组间的变化特点。结果 肾病大鼠肾组织PAI 1mRNA吸光度值为 1 6 ,蛋白质组化半定量为 (6 5 3± 10 2 ) % ,uPAmRNA吸光度值为 0 4 ,蛋白组化半定量为 (30 3± 4 2 ) % ;正常对照组PAI 1mRNA吸光度值为 0 5 ,蛋白质组化半定量为 (10 6± 2 4 ) % ,uPAmRNA吸光度值为0 7,蛋白组化半定量为 (85 3± 3 0 ) % ,两组两指标比较差异均有显著意义。经治疗后肾组织PAI 1mRNA吸光度值 0 9,蛋白组化半定量为 (2 0 7± 6 5 ) % ,趋于下降 ,uPAmRNA吸光度值为 0 8,蛋白组化半定量为 (93 1± 5 1) % ,趋于增高 (P <0 0 1)。结论 肾病病变进展中可出现纤溶系统的平衡紊乱 ,ACEI治疗可改善PA/PAI 1的异常表达 ,防止细胞外基质的异常沉积 。

Objective Many studies of recent years had demonstrated that the disorders of thrombic fibrinolytic system are a crucial inductor to the extracellular matrix (ECM) production and accumulation in renal tissues during chronic or progressive renal diseases, as well as to the renal damage of the thrombotic microangiopathy At the same time, the proliferation effect of rennin angiotensin system also plays an important role on these injuries Therefore, the investigation for the effects and interfering mechanism of angiotensin converting enzyme inhibitor (ACEI) and AT1 receptor antagonist on renal damage has become to a significant researching target in this field recently The study here was designed to detect the mRNA and protein expressions of urokinase type plasminogen activator (uPA) and type 1 plasminogen activator inhibitor (PAI 1) in renal tissues of nephrotic young rats and the interfering effects of ACEI treatment Methods Sixty Wistar rats at 4 months old were chosen in this experiment, 45 rats as the nephrotic group were injected with adriamycin via tail vein for two times, and other 15 rats as the control group were injected with 0 9% saline Two weeks after the injections the nephrotic model was established, which was proved by the blood and urine parameters and the renal pathologic changes All rats were further randomly divided into untreated group, ACEI treated group and control group, 15 rats in each group After treated with ACEI for 12 weeks, the blood pressure, body weight, proteinuria and serum biochemical parameters were measured, respectively The renal morphologic changes were observed on PAS staining slides, the mRNA and protein expressions of PAI 1 and uPA were detected by Northern blot analysis and immunochemical staining Results The expressions of PAI 1 mRNA ( A =1 6) and protein [(65 3±10 2)%] in renal tissues in untreated group increased, but the expressions of uPA [mRNA A =0 4; protein expression (30 3±4 2)%] decreased significantly compared to the control group [PAI 1 mRNA A =0 5; protein (10 6±2 4)%, uPA mRNA A =0 7; protein (85 3±3 0)%] In contrast, PAI 1 mRNA ( A =0 9) or protein (20 7±6 5)% decreased and uPA [mRNA A =0 8; protein (93 1±5 1)% ] markedly increased after the treatment with ACEI ( P <0 01) Conclusions The unbalance of thrombic fibrinolytic system was an important pathophysiologic event during glomerulosclerosic and tubulointerstitial fibrotic lesions The increased expression of PAI 1 and the decreased expression of uPA might induce the efficiency of the endogenous fibrinolytic system ACEI treatment could prevent the accumulation of ECM, which may be mediated by PAI 1 and other cytokines in renal tissues