Modulation of postsurgical macrophage function by postsurgical polymorphonuclear leukocytes]

Rapid and transient influx of polymorphonuclear leukocytes (PMN) is observed prior to accumulation of macrophages after surgical trauma. Rabbits underwent intestinal reanastomosis and at various times peritoneal exudate cells were collected and separated using a Percoll gradient. Postsurgical macrophages were incubated with PMN spent media obtained from various postsurgical periods. Macrophage release of O2- had already increased at 2 hr after surgery, reached peak levels at 6 hr and decreased by 24 hr. PMN spent media from 6 hr postsurgical cells functioned as a suppressor, whereas 12 or 24 hr PMN spent media increased the O2- release from the macrophages harvested at 6 and 12 hr after surgery. Plasminogen activator (PA) activity in the macrophage spent medium was elevated at 24 hr after surgery by exposure to PMN spent media, however no effects were observed on macrophages harvested within 12 hr after surgery. PA inhibitory activity was reduced at 2 hr after surgery, and gradually increased, but no effects of PMN spent media on the PA inhibitory activity was observed. Thus, soluble factors secreted into the medium by PMN may modulate macrophage metabolism in stages as the macrophages differentiate and promote wound repair.