大鼠体外循环后血浆二胺氧化酶与小肠黏膜基质蛋白变化的相关性研究

Study on the correlation between plasma diamine oxidase activity and the changes of extracellular matrix of intestinal mucosa in rats after cardiopulmonary bypass

目的探讨大鼠体外循环(CPB)后血浆二胺氧化酶活性与小肠黏膜细胞外基质蛋白变化的相关性,为阐明CPB后肠黏膜屏障损害的发生机制提供依据。方法健康成年雄性清洁级SD大鼠40只,随机分为CPB组(n=20)和假手术组(n=20),另取10只作为正常对照组。应用大鼠CPB模型进行操作并于转流结束后取血液标本及小肠组织标本,分光光度法测定血浆二胺氧化酶活性,免疫组化、放射免疫法和天狼星红苦味酸染色法测定小肠组织层粘连蛋白、Ⅳ型胶原和间质中Ⅰ、Ⅲ型胶原构成及含量变化,并进行统计学分析。结果 CPB组血浆中二胺氧化酶活性比假手术组和正常对照组显著增高(P=0.018);免疫组化显示CPB组小肠组织中层粘连蛋白和Ⅳ型胶原蛋白表达下降,出现上皮基底膜变薄,部分出现断裂消失,含量明显低于假手术组和正常对照组;CPB组小肠间质中Ⅰ型胶原、Ⅲ型胶原相间排列紊乱交错,Ⅰ型胶原减少明显。图像分析表明CPB组小肠组织胶原容积分数明显减少,而假手术和正常对照组之间无显著差异。线性回归及相关分析结果CPB后小肠黏膜层粘连蛋白、Ⅳ型胶原含量、胶原容积分数与血浆二胺氧化酶活性呈显著的负相关。结论 CPB后肠黏膜细胞外基质各成分含量下降与结构破坏是肠黏膜屏障功能损害的重要因素之一。

Objective To study the correlation between plasma diamine oxidase activity and the changes of extracellular ma- trix （ECM） of intestinal mucosa in rats after cardiopulmonary bypass （CPB）. Methods CPB model in rats was established. 40 SD rats were randomly divided into CPB group （n = 20） and sham -operation （SH） group （n = 20 ） , another 10 SD rats were taken as normal control （N） group. The plasma diamine oxidase （DAO） activity was measured by spectropbotometry, and the ECM component laminin （LN） and type Ⅰ , Ⅲ, Ⅳ collagens of intestinal mucosa were measured by immunohistocbemsitry, radioimmunology and picro- sirus red stained respectively. Results The plasma DAO activity in group CPB （1. 817± 0.359 U/ml） was significantly higher than those in group SH and N （ P = 0. 018 ）, while the contents of intestinal mucosa of LN and type Ⅳ collagen in group CPB were obviously decreased compared with those in group N and SH. It showed that the epithelial basement membrane of intestinal mucosa became thin- ner, partly ruptured and even disappeared by immunobistochemistry in group CPB. Type I and III collagens arranged interphasely but in disorder in group CPB, especially the type I collagen was significantly decreased. The collagen volume fraction （CVF） was signifi- cantly decreased in group CPB compared with group SH and N, but there is no difference between group SH and N. The changes of LN and type Ⅰ ,Ⅲ, Ⅳ collagens in the intestinal mucosa in group CPB were significantly negatively correlated with the activity of plasma DAO by linear correlative analysis. Conclusion The contents decrease of the components of ECM and the disorganization in intestinal mucosa were the important factors of intestinal barrier dysfunction after cardiopulmonary.