Superoxide anion production by postsurgical macrophages

Abstract

In order to characterize further the metabolic activity of postsurgical macrophages, we examined their potential to produce superoxide anion (O 2 −) in response to phorbol myristate acetate. Rabbits underwent resection and reanastomosis of their ileum after which peritoneal exudative cells (PEC) were collected at various times after surgery. Macrophages were isolated from the PEC with a discontinuous Percoll gradient. Thereafter, O 2 − release by these cells in response to phorbol myristate acetate (PMA) was determined by cytochrome c reduction. Macrophages recovered on postsurgical Days 3–7 expressed three- to fourfold greater O 2 − release than resident (nonsurgical) macrophages ( P < 0.001). In a time-course study of O 2 − release, maximum release occurred at 6 hr postsurgery, dropped to half of peak levels by Day 1, increased to peak levels again on Day 4, and remained increased until Day 7. The ability of macrophages to release O 2 − then gradually decreased, reaching control levels by Day 13. These data suggest that resident peritoneal macrophages are rapidly primed to produce enhanced amounts of superoxide anion in response to appropriate stimuli after surgery, and that macrophages subsequently recruited into the peritoneal cavity as a result of surgical trauma may also be primed for enhanced O 2 − release as they differentiate into modulator macrophages for tissue repair.