肢体缺血再灌注损伤对大鼠肠系膜微循环和血液流变性的变化及意义

The Changes and Impact of Mesentery Microcirculation and Hemorheology in Rats with Hind Limbs Ischemia-Reperfusion Injury

目的研究大鼠肢体缺血再灌注损伤时肠系膜微循环和血液流变性的变化,并探讨其意义。方法用BI-2000医学图像分析系统对肢体缺血再灌注大鼠的肠系膜微循环进行观察,大鼠随机分为6组(每组10只),在肢体缺血前(Control组),缺血4h(I组),再灌注20min(IR20组),再灌注60min(IR60组),再灌注120min(IR120组),再灌注200min(IR200组)时观察和记录肠系膜微循环改变,并测定血液流变学指标并于上述各时间点分别测定各组动物血液流变学指标及前列环素(Pros-tacyclin,PGI2)水平、血栓素A2(Thromboxane A2,TXA2)水平、前列环素/血栓素A2比值(PGI2/TXA2)。结果①与Control组比较,IR20组、IR60组大鼠肠系膜微动脉和微静脉管径缩小(P<0.01或P<0.05);IR120组、IR200组大鼠肠系膜微动脉和微静脉管径扩大(P<0.01或P<0.05);I组变化差异无显著性(P>0.05)。②与Control组比较,IR20组、IR60组、IR120组、IR200组大鼠肠系膜微动脉和微静脉血流速度依次减慢(P<0.01);I组变化差异无显著性(P>0.05)。③再灌注期,白细胞黏附聚集、白微栓及管周出血增多;血浆黏度、全血低切还原黏度(1s-1)、全血高切还原黏度(200s-1)、红细胞比容、红细胞聚集指数、血沉方程K值、红细胞刚性指数等指标增高,红细胞变形指数降低。血浆中PGI2、TXA2含量均于再灌注期先升高后降低,但PGI2/TXA2比值减小。结论大鼠肢体IR损伤时存在肠系膜微循环障碍和血液流变性异常,其发生可能与血管内皮的功能受损,PGI2/TXA2水平的平衡失调有重要关系。

Objective To investigate the changes of mesenteric microcirculation and hemorheology during ischemia - reperfusion（IR） injury in the hind limbs of rats as well as to explore its meanings. Methods 60 rats were randomly divided into the prior ischemia group（ control group）, 4h of ischemia group（ group Ⅰ）, 20 min of reperfusion group（ group IR20）, 60 min of reperfusion group（ group IR60）, 120 min of reperfusion group（ group IR120） and 200 min of reperfusion group（ group IR200）. The BI - 2000 medical analysis system was used to study the mesenteric microcirculation at the point of prior ischemia, 4h of ischemia, 20 min of reperfusion, 60 min of reperfusion, 120 min of reperfusion and 200 min of reperfusion respectively. At the same time, blood samples were obtained for measurement of the hemorheological indexes and the prostaglandin 12 （PGI2）, thromboxane A2 （TXA2 ）, PGI2/ TXA2 in plasma in different groups. Results （1）Compared with control group, the microvascular diameters decreased significantly （ P 〈 0.01 or P 〈 0.05） in group IR20 and group IR60, and increased significantly（ P 〈 0.01 or P 〈 0.05） in group IR120 and group IR200. Group Ⅰ had no significant difference from control group（ P 〉0.05）. （2）Compared with control group, the blood flow velocity of mesenteric microcirculation decreased significantly in turn（ P 〈0.01） in group IR20, group IR60, group IR120 and group IR200. Group Ⅰ had no significant difference from control group（ P 〉0.05）. （3）During the period of reperfusion, the number of adhesive leukocytes, microthrombus and hemorrhage increased; the hemorheological indexes such as ＂tip, L-qre, H-qre, Hct, EAI, ESRK and TK were improved while EDI reduced. During the period of reperfusion, the level of PGI2 and TXA2 in plasma dropped after rising while the PGI2/TXA2 decreased（ P 〈 0.01 or P 〈 0.05）. Conclusion There is failure of mesenteric microcirculation and abnormality of hemorheology in rats with IR injury of hind limbs. The above situation may have important relations with the injury of vascular endothelial cells and the unbalance of PGI2/TXA2.