Role of mast cells in the pathogenesis of postburn inflammatory response: reactive oxygen species as mast cell stimulators

Thermal trauma has a direct effect on mast cells, triggering the secretion of histamine. This secretion leads to an enhanced xanthine oxidase activity and an increased production of reactive oxygen species (ROS), the latter b rine produced after burns through differing mechanisms. As ROS have been sh own to have deleterious effects on cellular membranes. a lesion of the mast cell membrane could close the circle of autoinjury due to the vasoactive a ctions of mast cell mediators. Our studies were designed to assess the pote ntiality of ROS as stimulators of mast cell degranulation after burns by co mparing two groups of rats treated. respectively, with SOD and saline solut ion after a scald injury. Plasma levels of tryptase and histamine were anal yzed as markers of mast cell activity. A comparison of the mean increases o f tryptase between baseline and 3-h postburn levels in the two groups shows significant differences (p < 0.001) (control: 0.13 +/- 0.04, SOD: 0.03 +/- 0.01). When comparing the mean increases between the baseline and 3 h post burn levels of histamine in the two groups. significant differences were al so found (p < 0.001) (control group: 2.70 +/- 0.57, SOD group: 1.22 +/- 0.3 2). The lower levels of histamine and tryptase induced by SOD prov ides ind irect evidence that ROS are involved in the process, causing the release of such mediators by mast cells, which may in rum suggest that ROS can act as stimulators of mast cell degranulation in burns. (C) 2000 Elsevier Science Ltd & ISBI. All rights reserved.