大鼠肝微血管内皮功能的测定

Measurement of hepatic microvascular endothelial function in rats

目的探索建立测定大鼠肝微血管内皮功能的方法。方法取健康雄性Wistar大鼠24只随机分为假手术组(Sham)、肝缺血1 h、2 h和3 h组(OPT 1 h,OPT 2 h,OPT 3 h),于再灌注后不同时间分别测定各组大鼠肝微循环血流变化,以局部加热刺激试验和阻断后反应性充血(post occlusive reactive hyperemia,PORH)试验分别评价肝微血管内皮功能。结果正常大鼠肝微循环血流基线值为(198.30±8.98)PU,局部加热刺激后血流增加至(239.30±9.84)PU;PORH试验的基线、阻断后和反应性充血后的微循环血流值分别为(204.40±11.80)PU、(94.43±29.26)PU和(268.90±22.16)PU。大鼠肝经历不同时间的缺血和再灌注后,OPT 1 h、OPT 2 h和OPT 3 h组的加热刺激试验各血流值均显著低于Sham组(P<0.05),且OPT 3h组显著低于OPT 1 h组(P<0.01)和OPT 2 h组(P<0.05)。计算各组各时间点加热后的血流增加量?PU,结果表明OPT1 h组在再灌注60 min和90 min时的?PU值分别为(57.33±4.63)PU和(50.30±1.76)PU,明显高于Sham组的(31.40±4.80)PU和(30.00±4.41)PU(P<0.05)。OPT 3 h组在再灌注60 min时的?PU为(18.00±4.66)PU,明显低于Sham组和OPT 1 h组(P<0.05)。Sham、OPT 1 h、OPT 2 h和OPT 3 h组PORH试验的PF-BZ值分别为(187.32±15.00)PU、(144.90±9.94)PU、(91.31±4.48)PU和(26.92±9.43)PU,其中OPT 2 h组和OPT 3 h组的PF-BZ值显著低于Sham组和OPT 1 h组的相应值(P<0.05),且OPT 3 h组低于OPT 2 h组的相应值(P<0.05)。结论大鼠肝微血管具有对局部加热刺激和PORH作出反应的能力;严重的肝缺血再灌注损伤可导致肝微血管内皮功能障碍,而局部加热刺激试验和PORH试验可以用于评价肝微血管内皮功能。

Objective To establish a method to evaluate the hepatic microvascular endothelial function in rats. Methods Twentyfour adult male Wistar rats were randomly divided into sham group and three ischemic groups with 1 h, 2 h and 3 h of liver ischemia（OPT 1 h, OPT 2 h and OPT 3 h）. After reperfusion at different time points, the hepatic microcirculatory blood flow was measured. The hepatic microvascular endothelial function was assessed by local heating stimulation assay and post occlusive reactive hyperemia（PORH） assay. Results The baseline hepatic microcirculatory blood flow in normal rats was（198.30±8.98） PU. After local heating stimulation, the blood flow increased to（239.30±9.84） PU. In PORH assay of normal rat, the values of microcirculatory liver blood flow at baseline, post occlusion and hyperemia were（204.40±11.80） PU,（94.43±29.26） PU and（268.90±22.16） PU, respectively. After ischemia and reperfusion, the liver microcirculatory blood flow of OPT 1 h, OPT 2 h and OPT 3 h groups at baseline and post heating were significantly lower than those of sham group（P〈0.05）, and it was significantly lower in OPT 3 h group than OPT 1 h group（P〈0.01） and OPT 2 h group（P〈0.05）. After calculating the heating-induced increase of microcirculatory liver blood flow（？PU） of each group, we found that the ？PUs of OPT1 h group at 60 min and 90 min after reperfusion were significantly higher than those of sham group [（57.33±4.63） PU vs（31.40±4.80） PU,（50.30±1.76） PU vs（30.00±4.41） PU, P〈0.05]. The ？PU of OPT 3 h group at 60 min was significantly lower than those of sham and OPT 1 h group（P〈0.05）. In PORH assay, the PF-BZ values of OPT 2 h and OPT3 h groups were（91.31±4.48） PU and（26.92±9.43） PU, which were significantly lower than those of sham and OPT 1 h group [（187.32±15.00） PU and（144.90±9.94） PU, P〈0.05], and it was lower in OPT 3 h group than OPT 2 h group（P〈0.05）. Conclusion The microvasculature of rat liver can respond to local heating stimulation and PORH. Prolonged ischemia and reperfusion may result in the dysfunction of microvascular endothelia, and local heating stimulation assay and PORH assay can be used to evaluate the hepatic microvascular endothelial function.