急性肝内窦前型门静脉高压症大鼠肝内门体分流的变化及其意义

目的探讨急性肝内窦前型门静脉高压症时肝内门体分流的变化及其意义。方法经大鼠门静脉注射乳胶微球造成急性肝内窦前型门静脉高压症。采用肝山梨醇摄取率法测定功能性肝血流量和肝内门体分流量,采用放射性微球法测定肝内较大门体分流侧支(直径>15μm)的分流率。结果对照组肝山梨醇摄取率为(97.9±0.5)％,肝总血流量为每100g体重(2.52±0.23)ml／min。微球组,肝山梨醇摄取率锐减至(12.8±4.3)％,微球加肝动脉结扎组则下降至(4.1±0.7)％,t值为3.541和3.668,P值均<0.01;肝内门体分流量对照组、微球组、微球加肝动脉结扎组分别为每100g体重(0.06±0.02)、(1.46±0.15)和(1.16±0.19)ml／min,t值分别为5.468和6.869,P值均<0.01;门静脉血流量3组差异无统计学意义。结论肝内门体分流的直径大多<15μm。其开放可使70％的门静脉血绕过肝窦而直接注入肝静脉,并有效阻止了门静脉压力的升高。

Changes in intrahepatic portal systemic shunt flow in a rat model of acute intrahepatic presinusoidal portal hypertension

OBJECTIVES: To investigate the changes in intrahepatic portal systemic shunt flow (IHSF) and their relationship with microspheres induced acute portal hypertension. METHODS: Following acute intrahepatic presinusoidal obstruction by intraportal injection of 15 microm diameter microspheres in male Wistar rats, functional hepatic blood flow (FHBF) and IHSF were determined by hepatic sorbitol uptake methods. The percentage of large shunts of diameter > 15 microm were estimated by intraportal injection of 51Cr labeled 15 mum diameter microspheres. RESULTS: In normal control rats, hepatic sorbitol uptake was 97.9%+/-0.5% and IHSF was negligible, with FHBF equaling total hepatic blood flow [(2.52 +/- 0.23) ml/min x 100 g body weight-1]. Microsphere injection decreased sorbitol uptake to 12.8% +/- 4.3% and further to 4.1% +/- 0.7% when followed by hepatic arterial ligation. In the latter two groups, IHSF (1.46 +/- 0.15 and 1.16 +/- 0.19 ml/min x 100 g body weight-1, respectively) was not significantly different from portal venous flow [(1.36 +/- 0.20) and (1.20 +/- 0.20) ml/min x 100 g body weight-1, respectively; t = 2.013 and t = 2.116]. Portal venous flow remained at 70% of basal values and portal venous pressure only increased by 50% from baseline. 51Cr labeled microsphere shunt fraction through large shunts (> 15 microm) was less than 1.0%. CONCLUSION: Intrahepatic portasystemic shunts in the normal rat liver predominantly have diameters less than 15 microm and, when activated by intraportal injection of microspheres, they divert up to 70% of portal venous blood flow away from hepatic sinusoids and thereby they reduce acute increases in portal venous pressure.