Cytopathologic observations of the lung of adult newts (Cynops pyrrhogaster) on-board the space shuttle, Columbia, during the Second International Microgravity Laboratory experiments.

Four adult female Japanese newts, Cynops pyrrhogaster, were carried for 15 days aboard the orbiting space shuttle, Columbia, in July of 1994, as part of the Second International Microgravity Laboratory, IML-2 aquatic animal experiments. These previously fertilized newts, after stimulation with chorionic gonadotropin by a spaceflight adapted injection procedure, deposited numerous eggs for study of early development during weightlessness. The primitive saccular lungs of the two newts which survived the spaceflight revealed by TEM marked pulmonary cytopathologic changes including basal laminar separation, microvillar degeneration, and cytoplasmic granular changes in the primary granulated pneumocytes. Also, intracellular edema in the pulmonary collagenous matrix and vacuolar changes in the ciliated pulmonary lining cell type and in vascular endothelial cells were observed. These changes, triggered by the spaceflight, and not seen in controls also relying on respiration via the skin, may reflect a chronic mild hypoxia as it is known that newts undergoing oviposition are subject to increased oxygen demand.