Detection of leukocyte activation in pigs with neurologic decompression sickness.
BACKGROUND
In a porcine model of neurological decompression sickness (DCS), perivascular leukocyte activation was a consistent finding in biopsies of associated cutaneous DCS. This prompted examination of other organs for similar changes; multifocal leukocyte activation was found in the lungs (pneumonitis) and liver (hepatitis).


OBJECTIVE
DCS in pigs induces leukocyte aggregation and activation in the liver and lungs.


METHODS
Male Yorkshire swine, trained to run on a modified treadmill, were compressed to 200 ft of seawater (fsw) in a dry, air-filled compression chamber. Decompression varied according to the profile under study.


RESULTS
In 106 pigs, evidence for association of leukocyte aggregation and activation with the clinical diagnosis of neurologic DCS was sought. The incidence of pneumonitis (20/68, 29% with DCS; 4/38, 10% without DCS) and hepatitis (23/68, 33% with DCS; 4/38, 10% without DCS) were strongly correlated with the incidence of neurologic DCS via Pearson Chi-squared analysis (p = 0.026 pneumonitis and p = 0.008 hepatitis). Additionally, Kruskal-Wallis rank analysis for numbers of organs involved and incidence of neurologic DCS showed a strong correlation between the increasing occurrence of neurologic DCS and the involvement of both the liver and lungs (p = 0.004).


CONCLUSIONS
The results imply that, at least in pigs, DCS induces leukocyte aggregation and activation in the liver and lungs. These organs are not normally considered targets of DCS. Leukocyte aggregation in these organs may be related to their roles as highly perfused organs. Leukocyte aggregation may be a marker for DCS, providing further evidence for wider, systemic effects of DCS.
Nyquist
Paul A
PA
Naval Medical Research Center, Bethesda, MD, USA.
Dick
Edward J
EJ
Buttolph
Thomas B
TB
D000704:Analysis of Variance; D000818:Animals; D015415:Biomarkers; D003665:Decompression Sickness / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D004195:Disease Models, Animal; D004242:Diving / Q000009:adverse effects; D006505:Hepatitis / Q000276:immunology / Q000473:pathology; D008099:Liver / Q000276:immunology* / Q000473:pathology; D008168:Lung / Q000276:immunology* / Q000473:pathology; D008297:Male; D018375:Neutrophil Activation; D011014:Pneumonia / Q000276:immunology / Q000473:pathology; D018709:Statistics, Nonparametric; D013552:Swine
D015415:Biomarkers