Histamine dihydrochloride protects against early alcohol-induced liver injury in a rat model

Inflammation of the liver may be caused by a variety of factors that include infectious agents and toxins. Reactive oxygen species (ROS) generated by the NADPH oxidase in Kupffer cells and infiltrating leukocytes play an important role in the pathogenesis of early alcohol-induced hepatitis. Histamine dihydrochloride (histamine) suppresses the generation of ROS through the histamine type-2 receptor (H2 receptor). Histamine was studied as a potential protective treatment against early alcohol-induced liver injury in an experimental hepatitis model. Female Wistar rats were given ethanol (5 g/kg) intragastrically by gavage once daily for 4 weeks, while a control group not receiving ethanol was fed an isocaloric high-fat diet. Animals receiving ethanol had elevated serum levels of alanine and aspartate transaminase (ALT/AST) and developed steatosis, inflammation, and necrosis of the liver. Histamine treatment (0.5 or 5.0 mg/kg, twice daily) protected against this liver injury as evident by normal serum transaminase levels and significantly reduced liver pathology scores. Ranitidine (10 mg/kg), an H2 receptor antagonist, blocked the protective effect of histamine, indicating that the histamine effect is predominantly mediated through the H2 receptor. In conclusion, these results suggest that histamine protects against early alcohol-induced liver injury in rats.