In vivo administration of tolmetin in hyaluronic acid modulates protease levels in postsurgical macrophage-conditioned media

Tolmetin sodium in a hyaluronic acid carrier (tolmetin-HA) was previously shown to reduce adhesion formation and alter the kinetics and levels of cellular influx into the peritoneal cavity after surgery. In this study, the effect of tolmetin-HA on the level of protease activity in macrophage-conditioned media was determined. The level of collagenase activity in macrophage-conditioned media was supressed at 12 and 24 h after administration of tolmetin-HA. Alternatively, the peak level of elastase activity measured in macrophage-conditioned media was unchanged after tolmetin-HA treatment, but the kinetics of expression of maximal protease activity was delayed from 12 h in the control surgical rabbits to 24 h in tolmetin-HA-treated rabbits. Elevated plasminogen activator activity was detected in acid-treated conditioned media from the tolmetin-HA-treated rabbits when compared to control levels. However, no alteration in the level of plasminogen activator inhibitor activity was present in conditioned media of macrophages harvested from tolmetin-HA-treated rabbits compared to controls. These data suggest that tolmetin-HA treatment altered the levels of neutral protease activity secreted by postsurgical macrophages and may therefore elevate the fibrinolytic potential of the peritoneal cavity after surgery.