Intravenous injection of lipopolysaccharide and D-galactosamine, at doses of 0.2 μg/kg and 800 mg/kg, respectively, elicited massive hepatic necrosis within 24 hr in C3H/HeN mice. The plasma L-alanine aminotransferase (ALT, E.C. 22.214.171.124) or L-aspartate aminotransferase (AST, E.C. 126.96.36.199) activities at this point reached more than 2,000 IU/L. However, overt hepatic injury as evaluated by the plasma aminotransferase activities did not develop in mice in which only lipopolysaccharide or only D-galactosamine was injected. No tumor necrosis factor—like activities could be detected in the plasma of galactosamine- and lipopolysaccharide-injected mice as determined by the assay of cytotoxicity to highly tumor necrosis factor—sensitive L-P3 cells through the experimental period of 24 hr. However, passive immunization against mouse tumor necrosis factor—α with polyvalent rabbit anti-mouse tumor necrosis factor—α antiserum, which was able to neutralize the cytotoxic effects of recombinant mouse tumor necrosis factor—α on L-P3 cells, could protect the mice from the development of hepatic injury in a dose-dependent manner. Simultaneous injection of recombinant human tumor necrosis factor—α, instead of lipopolysaccharide, with 800 mg/kg of D-galactosamine in lipopolysaccharide-resistant C3H/HeJ mice sensitized the animals more than one thousand-fold to the development of hepatic injury. The livers appeared to be morphologically similar to those of galactosamine- and lipopolysaccharide-injected C3H/HeN mice.
These results suggest that endogenous tumor necrosis factor—α participates in the pathogenesis of lipopolysaccharide-elicited hepatic injury, and that tumor necrosis factor plays a crucial role in the development of liver necrosis in galactosamine-sensitized mice. (HEPATOLOGY 1990;12:1187–1191).