CYTOPATHOLOGIC OBSERVATIONS OF THE LUNG OF ADULT NEWTS (CYNOPS-PYRRHOGASTER) ON-BOARD THE SPACE-SHUTTLE, COLUMBIA, DURING THE 2ND INTERNATIONAL MICROGRAVITY LABORATORY EXPERIMENTS

Four adult female Japanese newts, Cynops pyrrhogaster, were carried fo r 15 days aboard the orbiting space shuttle, Columbia, in July of 1994 , as part of the Second International Microgravity Laboratory, IML-2 a quatic animal experiments. These previously fertilized newts, after st imulation with chorionic gonadotropin by a spaceflight adapted injecti on procedure, deposited numerous eggs for study of early development d uring weightlessness. The primitive saccular lungs of the two newts wh ich survived the spaceflight revealed by TEM marked pulmonary cytopath ologic changes including basal laminar separation, microvillar degener ation, and cytoplasmic granular changes in the primary granulated pneu mocytes. Also, intracellular edema in the pulmonary collagenous matrix and vacuolar changes in the ciliated pulmonary lining cell type and i n vascular endothelial cells were observed. These changes, triggered b y the spaceflight, and not seen in controls also relying on respiratio n via the skin, may reflect a chronic mild hypoxia as it is known that newts undergoing oviposition are subject to increased oxygen demand.