l-663536 and Liver-Diseases

Hepatic ischemia-reperfusion injury (I/R) may occur in transplantation, trauma, and elective hepatic resections. Leukotrienes have been shown to play a major role in hepatic I/R injury. Five-lipoxygenase enzyme is an important enzyme in the production of leukotrienes from arachidonic acid. MK-886 is an inhibitor of 5-lipoxygenase, and montelukast is a cysteinyl leukotriene receptor antagonist. The aim of this study was to investigate whether MK-886 and montelukast are effective in preventing hepatic I/R injury.. Rats were divided into five groups consisting of seven rats in each: (1) Control I/R, (2) Control-montelukast, (3) Control-MK-886, (4) I/R+montelukast, and (5) I/R+MK-886. Thirty min of total hepatic vascular occlusion and then 60 min reperfusion were performed to animals in groups 1, 4, and 5. In groups 2 and 4, montelukast, and in groups 3 and 5, MK-886 was applied intraperitoneally before and during the surgical procedures.. Apoptosis in the liver and intestine decreased significantly in the I/R+montelukast and I/R+MK-886 groups compared with the I/R group. Tissue malondialdehyde levels and glutathione consumptions also decreased significantly in the I/R+montelukast and I/R+MK-886 groups compared with the I/R group. The difference in serum alanine aminotransferase and aspartate aminotransferase levels between the groups did not reach significance.. Montelukast and MK-886 were found to be effective in prevention of liver and intestine injury by reducing apoptosis and oxidative stress in a hepatic I/R model. Anti-inflammatory properties and inhibition of lipid peroxidation by montelukast and MK-886 could be protective for these organs in I/R injury.

Topics: Acetates; Animals; Cyclopropanes; Disease Models, Animal; Indoles; Leukotriene Antagonists; Lipoxygenase Inhibitors; Liver Diseases; Male; Quinolines; Rats; Rats, Wistar; Reperfusion Injury; Sulfides

alpha-naphthylisothiocyanate (ANIT) administration to rats results in periportal hepatic inflammation and injury. Glutathione (GSH) appears to be necessary for the liver injury to occur. The leukotrienes (LTs) are metabolites of arachidonic acid and potent mediators of inflammation that have been implicated in certain liver injury models. Inasmuch as GSH is a cofactor for the synthesis of cysteinyl-LTs and since inflammation is a prominent component of ANIT injury, we hypothesized that LTs are involved in producing the hepatic insult that results from ANIT administration. To test this hypothesis, rats were treated with one of several inhibitors of LT biosynthesis, A63162, Zileuton or MK-886. Each of these agents prevented the formation of LTB4 in Ca++ ionophore-stimulated whole blood from rats treated with the inhibitors. A63162 attenuated the hepatic parenchymal injury caused by ANIT and resulted in a modest decrease in ANIT-induced cholestasis. In contrast, neither Zileuton nor MK-886 attenuated liver injury. AT-125 (Acivicin) inhibits gamma-glutamyl transferase (GGT), the enzyme that catalyzes the formation of LTD4 from LTC4. AT-125 pretreatment did not prevent ANIT-induced hepatic parenchymal insult. It did, however, ameliorate the cholestasis caused by ANIT. In conclusion, the partial protection afforded by A63162 and AT-125 likely results from effects unrelated to the formation of LTs, since Zileuton and MK-886 inhibited LT synthesis without affording protection. The lack of protection by Zileuton and MK-886 in the face of LT synthesis inhibition suggests that LTs are not necessary for the expression of injury after ANIT administration.

Topics: 1-Naphthylisothiocyanate; Acetamides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Calcimycin; Chemical and Drug Induced Liver Injury; Disease Models, Animal; Glutathione; Hydroxyurea; Indoles; Inflammation; Leukotriene Antagonists; Leukotrienes; Lipoxygenase Inhibitors; Liver; Liver Diseases; Male; Phenyl Ethers; Rats; Rats, Sprague-Dawley