Urodelean amphibians in studies on microgravity: effects upon organ and tissue regeneration

Abstract

Results obtained from nine experiments performed onboard Russian biosatellites have shown that microgravity promotes tissue regeneration in the newt, Pleurodeles waltl. The effect has been reproduced in all flights for eye tissues (lens and retina), limbs and tail. The effect was demonstrated in an 1.5- to 2-fold increase in cell proliferation in the early stages of regeneration in space flight. Animals “flown” intact and operated on after flight regenerated faster than controls and showed a long-lasting micro-“g” effect. The most recent experiment was aboard the Bion-11 satellite. This test was performed to study the effect of microgravity on neuronal retinal regeneration after an optic nerve resection in the newt. The results showed increased retinal regeneration as measured by tritiated thymadine uptake and glial fibrillar acidic protein immunostaining. There was an increase in thymidine uptake and glial fibrillar acidic protein immunostaining in the microgravity animals vs controls. The possibility of altered gravity stress proteins is discussed.—Hans E. Grossniklaus