肾性高血压模型大鼠左心室壁Ⅰ、Ⅲ型胶原网络重建

Network remodeling of collagenⅠand Ⅲ protein in the heart of renal hypertension rats

目的探讨肾性高血压大鼠左心室壁重构过程中Ⅰ、Ⅲ型胶原分布的变化规律。方法采用双侧肾动脉狭窄法制作动物模型,32只SD大鼠随机分为假手术组、术后2周组、术后5周组和术后7周组,利用无创动物血压分析测试仪评价高血压动物模型质量,免疫组织化学、Western blotting和图像分析方法检测各组左心室肌组织Ⅰ、Ⅲ型胶原的改变。结果与假手术组相比,Ⅰ、Ⅲ型胶原网络在术后2周均无明显变化,术后5周心肌细胞及肌束周围Ⅰ型胶原粗细纤维束呈断裂、聚集或部分缺如。心室壁小动脉管壁Ⅰ型胶原鞘不规整,纤维束断裂,胶原聚集或堆积,血管外膜粗纤维束向间质延伸;术后5周组肌细胞周围Ⅲ型胶原粗、细纤维束均出现严重松散或紊乱;血管壁Ⅲ型胶原鞘呈现松散现象。图像分析结果显示:术后5周组与术后7周组相比,Ⅰ型胶原平均吸光度和平均面积比均存在显著差异(P<0.05);Ⅲ型胶原平均吸光度各组间无显著差异(P>0.05),平均面积比术后2周组与术后5周组之间差异显著(P<0.05)。Western blotting检测结果表明,手术5周后Ⅰ型胶原蛋白表达量呈增高趋势,Ⅲ型胶原蛋白表达量呈降低趋势。结论高血压可导致左室壁Ⅰ、Ⅲ型胶原网络发生重建或破坏,血管外膜胶原结构严重受损。

Objective To explore the network remodeling of collagen I and Ⅲ protein in the heart of renal hypertension rats. Methods The animal model was prepared by bilateral renal artery stenosis. Thirty-two SD rats were randomly divided into sham operation group, two weeks group, five weeks group and seven weeks group after operation. The model quality of hypertensive rats was assessed with noninvasive blood pressure analysis. The variation characteristics of collagen I and m in left ventricular wall were detected by immunohistochemistry and Western blotting, and the quantitive analysis was performed with the microscopic image analysis system. Results The collagen I and Ⅲ networks had no noticeable change at the second week after operation, but at the fifth week after operation, the thick fibers of collagen I around cardiomyocyte bundle were seen markedly broken and gathered together, or absent. The broken or accumulated fibers with irregular arrangement in collagen I sheath in tunica adventitia of arteriole were also detected. The thick and thin fiber bundles of the collagen Ⅲ around cardimyocyte became loose and disorder at the fifth week after operation, and the collagen Ⅲ sheath of tnnica adventitia of arteriole turned to be loose. The results of microscopic image analysis showed that the difference of the mean optical density value and the average area ratio of collagen I had both significance between the fifth week and the seventh week after operation （ P 〈 0. 05 ）. The difference of mean optical density value of collagen Ⅲ had no significance between groups （P 〉 0. 05） , and the difference of the average area ratio had significance between the second week and the fifth week group after operation （P 〈 0. 05 ）. The results of Western bohting showed that the expression level of collagen I was gradually increased, and collagen Ⅲ was gradually decreased from the fifth week after operation. Conclusion The hypertension may cause severe damage to collagen I and Ⅲ network of the left ventrieular wall and the tunica adventitia of the vessels.