Protective actions of aprotinin in acute traumatic shock.

The effect of the protease inhibitor, aprotinin, was examined in rats during traumatic shock. In sham-operated control rats, intravenous administration of aprotinin (20,000 or 40,000 KIU/kg) showed no immediate changes in the mean arterial blood pressure and heart rate. In rats subjected to Noble-Collip drum trauma, aprotinin at a dose of 20,000 KIU/kg prolonged survival time to 2.1 +/- 0.3 hr (p less than 0.05) and 40,000 KIU/kg prolonged the survival time of rats to a greater extent (3.1 +/- 0.4 hr, p less than 0.001) compared to rats given only its vehicle (1.1 +/- 0.2 hr, mean +/- SE). The improved survival was accompanied by inhibition of the plasma accumulation of the cardiotoxic peptide, myocardial depressant factor (MDF). However, aprotinin showed no inhibitory effect on the plasma accumulation of the lysosomal enzyme, cathepsin D. Aprotinin has a beneficial effect on traumatic shock in rats possibly by its potent inhibitory action on MDF formation.