Effects of space flight on rat erythroid parameters. Allebban, Z., L. A. Gibson, R. D. Lange, T. L. Jago, K. M. Strickland, D. L. Johnson, A. T. Ichiki. University of Tennessee Medical Center at Knoxville, Knoxville, Tennessee, 37920, U.S.A
APStracts 2:0444A, 1995.
Hematological studies were performed on twenty-one ground control rats and twenty-one rats flown during the Spacelab Life Sciences-2 (SLS-2) 14-day mission. Group A (n=5) was used to collect blood inflight and nine days post flight, group B, (n=5) was injected with recombinant human erythropoietin (rhEpo), group C (n=5) received saline as a control and group D, (n=6) was killed inflight and tissues collected. Results indicated no significant changes in peripheral blood erythroid elements between flight and ground control rats. The non -adherent bone marrow on flight day 13 (FD13) showed a lower number of recombinant rat IL-3 (rrIL-3)-responsive and rrIL-3 + rhEpo -responsive BFU-e's in flight rats compared to ground controls. On R+0, a slight increase in the number of rhEpo + rrIL-3-responsive BFU-e's of flight animals compared to ground controls was evident. On R+9, bone marrow from flight rats stimulated with rhEpo alone or rhEpo + rrIL-3 showed an increase in the number of CFU-e's and a decrease in BFU-e's compared to ground controls. This is the first time that animals were injected with rhEpo and subsequently blood and tissues were collected during the space flight to study the regulation of erythropoiesis in microgravity.

Received 29 December 1994; accepted in final form 21 September
1995.
APS Manuscript Number A1314-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 November 95