Pseudomonas aeruginosa exotoxin in mice: histopathology and serum enzyme changes.

The histopathology and serum levels of mice inoculated intravenously with Pseudomonas aeruginosa exotoxin were studied. The toxin exerted a marked effect on the liver but elicited no demonstrable microscopic changes in other organs. The microscopic lesions caused in the liver by a single injection of two 50% lethal doses (LD50) of toxin (2.3 mug) were characterized by necrosis, cellular swelling, and fatty change within 4--8 hr and near total hepatocellular necrosis at 48 hr. Hepatic necrosis was accompanied by a parallel rise in serum levels of aspartate and alanine aminotransferases and alkaline phosphatase. A single injection of 10 LD50 elicited similar but somewhat more rapid degeneration. No progressive lesions were seen after injection of toxoid or of 0.5 LD50 of toxin.