Neutrophil function and pO2 in irradiated skin- and skin-muscle-flaps

Results of earlier investigations have demonstrated impaired function of polymorph-nuclear cells (PMN) in previously irradiated tissue. This study was designed to examine the effect of local oxygen pressure (pO2) on neutrophil function in irradiated tissue. By choosing a pig model of irradiated and non-irradiated high perfusion wound environment (i.e. musculo-cutaneous (MC) flap) vs. a poor perfusion wound environment (i.e. random pattern (RP) skin flap), the effect of different pO2 levels on neutrophil phagocytosis and respiratory burst (H2O2 production) were measured at 6, 12, and 16 weeks after irradiation. In both kinds of irradiated flaps, pO2 levels and neutrophil function were significantly lower (RP: <20 mmHg; MC: 30 mmHg) than in corresponding flaps from non-irradiated tissue (RP: 26–28 mmHg; MC: 30–40 mmHg) and showed a progressive decline with increasing time interval after irradiation. Correlation between pO2 and phagocytosis (p=0.001) and H2O2 production (p=0.02) proved to be statistically significant for the irradiated random pattern flaps, but not for musculocutaneous flaps.