AIM:To produce a new rat model of portal hypertension by intraportal injection of microspheres. METHODS: Measured aliquots of single or different-sized microspheres (15,40,80&mgr;m) were injected into the portal vein to block intrahepatic portal radicals. The resultant changes in arterial,portal,hepatic venous and splenic pulp pressures were monitored.The liver and lungs were excised for histological examination. RESULTS: Portal venous pressure was elevated from basal value of 0.89-1.02 kPa to a steady-state of 1.98-3.19 kPa following the sequential injections of single or different-sized microspheres, with a markedly lowered mean arterial pressure. However, a small-dose injection of 80&mgr;m microspheres (1.8X10(5)) produced a steady-state portal venous pressure of 2.53 plus minus 0.17 kPa,and all rats showed normal arterial pressures. In addition, numerous microspheres were found in the lungs in all experimental groups. CONCLUSION: Portal hypertension can be reproduced in rats by intraportal injection of microspheres at a small dose of 80&mgr;m (1.8X105).Intrahepatic portal-systemic shunts probably exist in the normal rat liver.
AIM:To produce a new rat model of portal hypertension by intraportal injection of microspheres. METHODS: Measured aliquots of single or different-sized microspheres (15,40,80&mgr;m) were injected into the portal vein to block intrahepatic portal radicals. The resultant changes in arterial,portal,hepatic venous and splenic pulp pressures were monitored.The liver and lungs were excised for histological examination. RESULTS: Portal venous pressure was elevated from basal value of 0.89-1.02 kPa to a steady-state of 1.98-3.19 kPa following the sequential injections of single or different-sized microspheres, with a markedly lowered mean arterial pressure. However, a small-dose injection of 80&mgr;m microspheres (1.8X10(5)) produced a steady-state portal venous pressure of 2.53 plus minus 0.17 kPa,and all rats showed normal arterial pressures. In addition, numerous microspheres were found in the lungs in all experimental groups. CONCLUSION: Portal hypertension can be reproduced in rats by intraportal injection of microspheres at a small dose of 80&mgr;m (1.8X105).Intrahepatic portal-systemic shunts probably exist in the normal rat liver.