Nagata H, Sekizuka E, Morishita T, Houzawa S, Oshio C, Miura S, Tsuchiya M
Department of Internal Medicine, Saiseikai Central Hospital, Tokyo, Japan.
J Gastroenterol Hepatol. 1993 Jul-Aug;8(4):315-21. doi: 10.1111/j.1440-1746.1993.tb01520.x.
The effect of acute elevation of portal pressure on the blood flow of rat intestinal microvessels was studied using a laser Doppler velocimeter and in vivo microscopy. The total intestinal blood flow decreased when portal pressure increased more than +15 cmH2O above the basal value. Blood flow in villus capillaries did not change at portal pressures of +5 to +15 cmH2O, but did decrease at +20 cmH2O. Blood flow in muscle capillaries decreased at all steps of portal hypertension. Red blood cell velocity was decreased by portal hypertension in large venules, but not in small venules of the submucosa. Large venules, but not small venules, dilated in acute portal hypertension. Large arterioles in the submucosa constricted, while small arterioles dilated at portal pressures of +10 to +15 cmH2O. In conclusion, the intestinal microvascular flow response differs according to the degree of portal hypertension and the location on the microvascular tree. Blood flow in villus capillaries and in small submucosal venules is maintained at a small degree of portal hypertension.
采用激光多普勒血流仪和活体显微镜研究了门静脉压力急性升高对大鼠肠微血管血流的影响。当门静脉压力比基础值升高超过+15 cmH₂O时，肠总血流量减少。门静脉压力在+5至+15 cmH₂O时，绒毛毛细血管血流无变化，但在+20 cmH₂O时血流减少。在门静脉高压的各个阶段，肌层毛细血管血流均减少。门静脉高压使大静脉中的红细胞速度降低，但黏膜下层小静脉中的红细胞速度未降低。急性门静脉高压时，大静脉扩张，小静脉未扩张。黏膜下层的大动脉收缩，而在门静脉压力为+10至+15 cmH₂O时小动脉扩张。总之，肠微血管血流反应因门静脉高压程度和微血管树位置的不同而有所差异。在轻度门静脉高压时，绒毛毛细血管和黏膜下层小静脉的血流得以维持。
