[Changes in intrahepatic portal systemic shunt flow in a rat model of acute intrahepatic presinusoidal portal hypertension].
OBJECTIVE
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%.


CONCLUSIONS
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.
Li
Xiang-Nong
XN
Department of General Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou 221002, China. znli2002@yahoo.com.cn
Shi
Yang
Y
Ding
Wei
W
D000818:Animals; D006499:Hepatic Artery / Q000503:physiopathology*; D006503:Hepatic Veins / Q000503:physiopathology*; D006975:Hypertension, Portal / Q000139:chemically induced / Q000503:physiopathology*; D008863:Microspheres; D011169:Portal Vein / Q000503:physiopathology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar