concanavalin-a and beraprost

Studies of the molecular and cellular mechanisms of concanavalin A (ConA)-induced liver injury have provided important knowledge on the pathogenesis of many liver diseases involving hepatic inflammation. However, studies identifying hepato-protective factors based on the mechanistic understanding of this model are lacking. Evidence suggests that certain prostaglandin (PG) products of cyclooxygenase (COX)-1 and COX-2 provide important anti-inflammatory and cytoprotective functions in some pathophysiological states. In the present study, we demonstrate a protective role of COX-2 derived PGs in ConA-induced liver injury. COX-2(-/-) mice developed much more severe liver damage upon ConA treatment compared with wild-type and COX-1(-/-) mice. Treatment of COX-2(-/-) mice with misoprostol (a PGE(1/2) analog) or beraprost (a PGI(2) analog) significantly decreased ConA-induced liver injury. Data from both in vivo and in vitro experiments demonstrated that misoprostol and beraprost acted directly on hepatic leukocytes, including natural killer (NK)T and T cells, and down-regulated their production of interferon (IFN)-gamma, which are critical in mediating ConA-induced tissue damage. Collectively, the results provide strong evidence that the protective effects of COX-2 within the liver are mediated through the production of PGE(2) and PGI(2), which exert anti-inflammatory functions. These findings suggest that COX-2-derived PGs may have great therapeutic potentials in treating patients with inflammatory liver diseases.

Topics: Animals; Chemical and Drug Induced Liver Injury; Concanavalin A; Cyclooxygenase 2; Dinoprostone; Disease Models, Animal; Down-Regulation; Epoprostenol; Gene Expression Regulation; Gene Expression Regulation, Enzymologic; Inflammation; Interferon-gamma; Liver Diseases; Male; Mice; Mice, Knockout; Misoprostol; Mitogens

Prostacyclin (PGI(2)) is a potent mediator in the inflammatory and coagulation processes. The aim of this study was to test whether beraprost sodium, a PGI(2) analogue, could prevent experimental hepatic injury induced by concanavalin A (Con A), which is a model of fulminant hepatic failure.. Beraprost (100 microg/kg) was administered intraperitoneally simultaneously with Con A (40 mg/kg) in C57B6J mice. Blood circulation in the liver was determined by laser-Doppler flowmetry. Plasma levels of alanine aminotransferase (ALT), tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-6 were determined. Levels of TNF-alpha and IFN-gamma in culture supernatant of splenocytes were also determined.. Beraprost administration reduced the incidence of death following hepatic failure (76.5% vs. 29.4%, P<0.05). Plasma levels of ALT were significantly lower in the beraprost-treated group than in the control group, and in the former, there was concomitant suppression of the histological features of injury. Beraprost significantly increased hepatic blood flow volume in Con A-treated mice. Plasma levels of TNF-alpha and IFN-gamma were significantly reduced at 6 and 12 h after Con A injection, respectively, but the levels of IL-6 were increased at 6 h. In vitro, beraprost also suppressed Con A-induced TNF-alpha production in splenocytes, while it stimulated IFN-gamma production.. These findings imply that beraprost suppresses Con A-induced liver injury. These data also suggest that beraprost, which is clinically effective in treating pulmonary hypertension, may have therapeutic potential for preventing hepatic injury.

Topics: Animals; Concanavalin A; Epoprostenol; Interferon-gamma; Interleukin-6; Liver Circulation; Liver Failure, Acute; Male; Mice; Mice, Inbred C57BL; Nitric Oxide; Spleen; Tumor Necrosis Factor-alpha