AJP - Lung Cellular and Molecular Physiology, Vol 272, Issue 4 772-L778, Copyright © 1997 by American Physiological Society
Nuclear magnetic resonance study of lung water compartments in the rat
S. Shioya, M. Haida, M. Fukuzaki, D. Kurita, C. Tsuji, Y. Ohta and H. Yamabayashi
Department of Internal Medicine, Tokai University School of Medicine, Isehara, Japan.
Nuclear magnetic resonance transverse relaxation time (T2) was previously
measured in studies of lung water. The T2 decay curves for peripheral lung
tissue were found to be multiexponential with two T2 components: T2 fast
(T2f) and T2 slow (T2s). This behavior was explained by the
compartmentalization of water, in which the protons of water are restricted
and do not undergo rapid exchange between the compartments. We investigated
the origin of the water for these T2 components using excised rat lungs.
The effect of magnetic field inhomogeneity due to air-tissue interfaces was
examined by degassing some lungs. The contribution of intravascular water
was examined by perfusing the lungs with oil or NaCl solutions. Degassing
produced a greater increase in the T2f than the T2s component, indicating
that the water in the alveolar walls exposed to air spaces contributed to
the T2f. Perfusion with oil decreased the T2s, indicating that
intravascular water contributed to the T2s component. The effects of
intravascular osmotic pressure on the T2f and T2s components suggest that
intracellular water is related to the T2f component.
