The role of NO in macrophage dysfunction at early stage after burn injury

• Published in: Burns 2005-03, Vol.31 (2), p.138-144
• Main Authors: Luo, Gaoxing, Peng, Daizhi, Zheng, Junsong, Chen, Xiwei, Wu, Jun, Elster, Eric, Tadaki, Douglas
• Format: Article
• Language: English
• Subjects: Animals; Arginine - pharmacology; Burn; Burns - immunology; Burns - metabolism; Cell Division - drug effects; Cells, Cultured; Cyclooxygenase 2; Dinoprostone - metabolism; Dose-Response Relationship, Drug; Dysfunction; Early stage; Enzyme Inhibitors - pharmacology; Lymphocytes - immunology; Macrophage; Macrophages - drug effects; Macrophages - immunology; Macrophages - metabolism; Mice; Mice, Inbred BALB C; Nitric Oxide - biosynthesis; Nitric Oxide - physiology; Nitric Oxide Synthase - analysis; Nitric Oxide Synthase Type II; omega-N-Methylarginine - pharmacology; Prostaglandin-Endoperoxide Synthases - metabolism; Spleen - immunology; Tumor Necrosis Factor-alpha - metabolism
• ISSN: 0305-4179; 1879-1409
• DOI: 10.1016/j.burns.2004.09.009

To explore the role of nitric oxide (NO) in macrophage dysfunction at early stage after burn injury. Peritoneal macrophages were isolated and cultured from early stage burnt mice. NO production and inducible NO synthase (iNOS) expression in the macrophages were checked by the Greiss method and real-time PCR (TaqMan), respectively. l-Arginine, the substrate of NO producing, or N-monomethyl- l-arginine ( l-NMMA), a competing blocker of NOS was administered to the culture, the changes of NO, TNF-α and PGE2 productions were measured, additionally the changes of the iNOS, TNF-α and COX-2 expression were assayed by real-time PCR. After that, the effects of l-arginine and l-NMMA were determined on burnt macrophage influencing the proliferation of normal splenic lymphocytes. A large amount of NO was produced by macrophages from post burn hour 6 (6PBH) with a high level of iNOS expression. l-Arginine could increase NO production in a dosage-dependent manner, while l-NMMA attenuated NO production, but neither could affect iNOS expression. Moreover, l-arginine enhanced productions of both the latter produced TNF-α and PGE2 from burnt macrophages, and the expressions of TNF-α and COX-2 were improved significantly, while l-NMMA did reverse ways. It was found that macrophages from post burn hour 24 mice could inhibit Con A-stimulated normal splenic lymphocytes dramatically, l-NMMA could decrease this function significantly, but l-arginine could not influence the suppression. Our experiment indicated NO derived from burnt macrophage played a vital role in macrophage producing excessive TNF-α and PGE2, and suppressing lymphocyte function at early stage after burn injury.