Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl4-induced liver cirrhosis

AIM: To evaluate the changes in hepatic platelet activating factor (PAF) and its receptors and their effect on portal pressure of cirrhotic rats induced by CCl4. METHODS: A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCl4 for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS: Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels (P<0.01, P<0.01, P<0.05, respectively). Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats (P<0.01). Portal injection of PAF (1 g/kg WT) increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups (54% in control rats and 42% in cirrhotic rats). Injection of the PAF antagonist BN52021 (5 mg/kg WT) decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION: The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in cirrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics. (C) 2006 The WJG Press. All rights reserved.