Journal of Applied Physiology, Vol 77, Issue 5 2355-2359, Copyright © 1994 by American Physiological Society
Effect of hyperbaric oxygen on tissue distribution of mononuclear cell subsets in the rat
N. Bitterman, N. Lahat, T. Rosenwald, A. Kinarty, Y. Melamed and H. Bitterman
Israel Naval Medical Institute, Haifa, Israel.
In a previous study we found a significant temporary decrease in the ratio
of CD4/CD8 (helper, inducer/suppressor, cytotoxic) T lymphocytes in the
peripheral blood of healthy human volunteers after exposure to a single
commonly used profile of hyperbaric oxygen (HBO). The transient nature of
the changes suggested redistribution of T-cell subsets. The purpose of the
present study was to verify such a redistribution and to locate possible
target organs in an animal model. A single exposure of rats to HBO (0.28
MPa) induced a highly significant rapid decrease in the CD4/CD8 ratio in
peripheral blood count (P < 0.0001), confirming our previous findings in
humans. HBO also induced a significant increase in the CD4/CD8 ratio in the
lungs and lymph nodes (P < 0.001) and a significant decrease in the
ratio in the spleen (P < 0.01). Furthermore, exposure to HBO induced a
significant increase in T cells bearing surface interleukin-2 receptors in
the blood, spleen, lungs, and lymph glands (P < 0.001) and a significant
decrease in T cells expressing alpha beta-receptors in the lungs (P <
0.001) and lymph glands (P < 0.05). Our findings suggest rapid T-cell
activation after a brief exposure to HBO, with shifts of CD4 and CD8
subsets and variations in T-cell receptor type. These rapid changes in the
parameters of cell-mediated immunity may represent the activation of
protective mechanisms against the toxic effect of oxygen or the early
stages of pulmonary oxygen toxicity.
