Stress biomarkers in a rat model of decompression sickness.
BACKGROUND
Immune reactivity, stress responses, and inflammatory reactions may all contribute to pathogenic mechanisms associated with decompression sickness (DCS). Currently, there are no biomarkers for DCS. This research examined if DCS is associated with increased levels of biomarkers associated with vascular function, early/non-specific stress responses, and hypothalamic-pituitary-adrenal (HPA) axis stress responses.


METHODS
Rats undergoing a test dive to 175 ft of seawater (fsw) (6.2 ATA) for 60 min with a rapid decompression were observed for DCS (ambulatory deficit). Animals exercised on a rotating cage (approximately 3 m x min(-1)) throughout the dive and subsequent 30-min observation period. All animals were euthanized and blood and tissue samples (brain, liver, lung) were collected for analysis of CRP and ET-1 by ELISA and stress markers by PCR.


RESULTS
HO-1 and HSP-70 increased in the brain, and HO-1, Egr-1, and iNOS increased in the lungs of animals with DCS. There was no difference in any stress marker in the liver, or in serum levels of CRP or ET-1.


CONCLUSIONS
The results demonstrate that < 30 min after surfacing, there are genomic changes in animals with DCS compared with animals not showing signs of DCS. Identification of specific markers of DCS may permit use of such biomarkers as predictors of DCS susceptibility and/or occurrence.
Montcalm-Smith
Elizabeth
E
Naval Medical Research Center, Silver Spring, MD 20910-7500, USA.
Caviness
James
J
Chen
Ye
Y
McCarron
Richard M
RM
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D003665:Decompression Sickness / Q000209:etiology / Q000378:metabolism*; D004195:Disease Models, Animal; D004242:Diving / Q000009:adverse effects*; D019332:Endothelin-1 / Q000378:metabolism; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008168:Lung / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012623:Seawater; D013312:Stress, Physiological / Q000235:genetics / Q000378:metabolism*
D015415:Biomarkers; D019332:Endothelin-1; D018840:HSP70 Heat-Shock Proteins; D002097:C-Reactive Protein; D019001:Nitric Oxide Synthase; D051547:Heme Oxygenase-1