Is mannitol effective against platelet-activating factor (PAF)-induced liver damage in obstructive jaundice?

摘要

BACKGROUND/AIMS: Platelet-activating factor, is a unique phospholipid with a broad range of biological activities that may be relevant in the development of inflammatory reactions. Platelet-activating factor has been suspected to play an important role in liver pathophysiology. The cultured Kupffer and endothelial cells produce and release platelet-activating factor in order to facilitate communication between hepatic sinusoidal and parenchymal cells. In this study, in the experimental jaundice model, platelet-activating factor levels were measured in liver tissue and plasma and the possible effects of mannitol on this mediator were assessed. METHODOLOGY: The experimental model consisted of 7 rats in the control group (CG), 7 rats in the sham operation group (ShG), and 7 rats in the obstructive jaundice group (JG) created by ligating the common bile duct. The last group was the mannitol-treated jaundiced group (MJG) and all animals in this group received 20% mannitol in doses of 2 mL/day, intraperitoneally, following common bile duct ligation. A week later all animals were sacrificed and plasma and liver tissue samples were collected. Platelet-activating factor levels were measured by radioimmunoassay technique. RESULTS: Liver tissue platelet activating factor levels (pg/mg tissue protein) were 72 +/- 18 in the CG, 183 +/- 51 in the JG, 84 +/- 17 in ShG, and 124 +/- 36 in MJG. Plasma levels were 460 +/- 13, 1600 +/- 40, 560 +/- 19, and 1200 +/- 23, respectively. In both sample types, MJG and JG values were significantly different from CG and ShG as well. MJG levels were also different from JG. CONCLUSIONS: These results showed that plasma and liver tissue platelet-activating factor levels are increased in experimental obstructive jaundice; and activation of this mediator contributes to the ongoing liver injury. Mannitol may improve or lessen this damage.