The role of NO in macrophage dysfunction at early stage after burn injury.
OBJECTIVE
To explore the role of nitric oxide (NO) in macrophage dysfunction at early stage after burn injury.


METHODS
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-alpha and PGE2 productions were measured, additionally the changes of the iNOS, TNF-alpha 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.


RESULTS
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-alpha and PGE2 from burnt macrophages, and the expressions of TNF-alpha 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.


CONCLUSIONS
Our experiment indicated NO derived from burnt macrophage played a vital role in macrophage producing excessive TNF-alpha and PGE2, and suppressing lymphocyte function at early stage after burn injury.
Luo
Gaoxing
G
Burn Research Institute, Southwestern Hospital, Third Military Medical University, 30 Gaotanyan Street, Chongqing 400038, China.
Peng
Daizhi
D
Zheng
Junsong
J
Chen
Xiwei
X
Wu
Jun
J
Elster
Eric
E
Tadaki
Douglas
D
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D002056:Burns / Q000276:immunology* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008214:Lymphocytes / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000032:analysis; D052247:Nitric Oxide Synthase Type II; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D013154:Spleen / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D014409:Tumor Necrosis Factor-alpha; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone