The inflammatory reaction in an experimental model of open wounds in the rat. The effect of arachidonic acid metabolites.

The study concerned the effect of arachidonic acid metabolites on the inflammatory reaction in granulation tissue of open wounds in rats. Metabolites or inhibitors were applied in a wound chamber attached to circular, open, full-thickness skin wounds 5 days post-wounding. The adjacent wound served as control. Blood flow, albumin extravasation and accumulation of polymorphonuclear leucocytes (PMNLs) were measured in the granulation tissue. Prostaglandin E2 (PGE2 5.7 microM) increased blood flow and albumin extravasation by 95 and 16%, respectively, without affecting PMNLs. Leukotriene B4 (LTB4 2.7 microM) increased PMNL accumulation by 142% without altering albumin extravasation. Indomethacin (28 microM, repeatedly) did not affect blood flow or albumin extravasation, but increased PMNL accumulation by 21%. Methylprednisolone (3.3 mM, repeatedly) reduced blood flow and albumin extravasation by 29 and 31%, respectively, without influencing PMNLs. The granulation tissue obviously responds to exogenous PGE2 and LTB4. Endogenous arachidonic acid metabolites seem to play only a minor role in the inflammatory process in this model.