Figure 1. Norepinephrine suppresses wound macrophage phagocytic efficiency.
Macrophages isolated from 120-hour wounds were placed in culture for 18 hours with media alone (Control, red), physiologic norepinephrine (Phys NE, 10−9 M, blue), or pharmacologic norepinephrine (Pharm NE, 10−6 M, green) and phagocytosis of E.coli was assessed. (A) Norepinephrine-treatment did not alter the percentage of macrophages that engaged in phagocytosis (p=NS). (B) Representative phagocytosis histograms for control (red), physiologic NE-treated (blue) and pharmacologic NE-treated (green) wound macrophages. Both physiologic- (blue) and pharmacologic-dose norepinephrine treatment (green) resulted in a shift of the phagocytosis curve to the left, indicating fewer bacteria ingested per cell. The geometric mean of each curve was calculated to provide the phagocytic index (C) and was analyzed by two-way ANOVA followed by Bonferonni post-comparison testing. Both physiologic- and pharmacologic-dose norepinephrine suppressed the phagocytic efficiency of 120-hour wound macrophages (*p<0.001). (D) Representative confocal microscopy image demonstrating phagocytosis of GFP-E.coli (green, upper right) by a macrophage (phycoerythrin-F4/80, red, upper left). False-DIC (white, lower left) delineates the boundaries of the macrophage, demonstrating that the visualized bacteria are intracellular (merged image, lower right).