Inhibition of zymosan-induced air-pouch inflammation by rat seminal vesicle protein and by its spermidine derivative.

The anti-inflammatory effect of one of the major proteins secreted by rat seminal vesicles (SVIV) and of its spermidine derivative (Spd2-SVIV) was evaluated by measuring polymorphonuclear leukocyte migration, protein release, platelet-activating factor (PAF) and prostaglandin E2 levels in the mouse air-pouch exudate following zymesan treatment. Both proteins were found to markedly reduce dose dependently PAF and prostaglandin E2 levels in the exudate as well as the other parameters. Concurrent injection of either arachidonic acid or PAF, directly into the pouch, significantly counteracted the anti-inflammatory effect of SVIV and of its polyaminated derivative. These results support the notion that the molecular mechanism of the anti-inflammatory activity of SVIV and Spd2-SVIV is linked to the inhibition of both phospholipase A2 and acetyl:lyso-PAF acetyltransferase.