The researchers studied the effects of arsenic trioxide (As2O3) on rat livers using a special perfusion method. They gave different doses of As2O3 to rats and monitored liver function and pathology. They found that high doses of As2O3 caused liver damage, but it was reversible at a moderate dose of 1.5 mg/kg. The liver enzymes ALT and AST increased after As2O3 exposure, peaking on the first day and returning to normal after a few days. The highest dose of As2O3 led to liver cell death, while lower doses did not. The concentration of As2O3 in the liver was much higher than in the rest of the body during perfusion. Overall, the study shows that As2O3 can be toxic to the liver, but the damage is reversible at a certain dose.