title: Acclimation to decompression: stress and cytokine gene expression in rat lungs.
abstract: Previous studies demonstrated that animals exposed to repeated compression-decompression stress acclimated (i.e., developed reduced susceptibility) to rapid decompression. This study endeavored to characterize inflammatory and stress-related gene expression and signal transduction associated with acclimation to rapid decompression. Rats were divided into four groups: 1) control-sham: pressure naïve rats; 2) acclimation-sham: nine acclimation dives [70 feet seawater (fsw), 30 min]; 3) control-dive: test dive only (175 fsw, 60 min); and 4) acclimation-dive: nine acclimation dives and a test dive. After the test dive, rats were observed for decompression sickness (DCS). Expression of 13 inflammatory and stress-related genes and Akt (or PKB, a serine/threonine protein kinase) and MAPK phosphorylation of lung tissue were examined. The expression of immediate early gene/transcription factor early growth response gene 1 (Egr-1) was observed in both control and acclimation animals with DCS but not in animals without DCS. Increased Egr-1 in control-dive animals with DCS was significantly greater than in acclimation-dive animals with DCS. TNF-α, IL-1β, IL-6, and IL-10 were significantly elevated in control-DCS animals. Acclimation-DCS animals had increased TNF-α, but there was no change in IL-1β, IL-6, and IL-10. High levels of Akt phosphorylation were observed in lungs of acclimation-sham, acclimation-dive, and control-dive animals; phosphorylated ERK1/2 was only observed in animals with DCS. This study suggests that activation of ERK1/2 and upregulation of Egr-1 and its target cytokine genes by rapid decompression may play a role in the initiation and progression of DCS. It may be that the downregulated expression of these genes in animals with DCS is associated with previous exposure to repeated compression-decompression cycles. This study represents an initial step toward understanding the molecular mechanisms associated with acclimation to decompression.
authors.affiliation: Department of NeuroTrauma, Naval Medical Research Center, 503 Robert Grant Ave., Silver Spring, MD 20910-7500, USA. Ye.Chen@med.navy.mil
authors.forename: Ye
authors.initials: Y
authors.lastname: Chen
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Montcalm-Smith
authors.forename: Christine
authors.initials: C
authors.lastname: Schlaerth
authors.forename: Charles
authors.initials: C
authors.lastname: Auker
authors.forename: Richard M
authors.initials: RM
authors.lastname: McCarron
mesh_terms: D000064:Acclimatization / Q000235:genetics / Q000502:physiology*; D000818:Animals; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D003664:Decompression / Q000379:methods; D003665:Decompression Sickness / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D051766:Early Growth Response Protein 1 / Q000235:genetics; D015870:Gene Expression; D007249:Inflammation / Q000235:genetics / Q000378:metabolism; D007378:Interleukins / Q000235:genetics* / Q000378:metabolism; D008168:Lung / Q000378:metabolism / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000235:genetics; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics / Q000502:physiology; D010766:Phosphorylation / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D016207:Cytokines; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D051058:Oncogene Protein v-akt; D020929:Mitogen-Activated Protein Kinase Kinases