Journal of Applied Physiology, Vol 73, Issue 2 82S-89S, Copyright © 1992 by American Physiological Society
Spaceflight and growth effects on muscle fibers in the rhesus monkey
S. C. Bodine-Fowler, R. R. Roy, W. Rudolph, N. Haque, I. B. Kozlovskaya and V. R. Edgerton
Division of Orthopaedics, School of Medicine, University of California, San Diego, La Jolla 92161.
Spaceflight causes considerable atrophy in hindlimb muscles of the rat. The
purpose of this study was to investigate the effect of a 14-day spaceflight
(COSMOS 2044) on selected morphological and metabolic properties of single
muscle fibers in a nonhuman primate, Macaca mulatta. Biopsies were taken
from the soleus (Sol), medial gastrocnemius (MG), and tibialis anterior
(TA) muscles of two rhesus monkeys 107 days before flight and 24 h after
return from flight. Muscle biopsies were taken from two independent sites
in each muscle by use of a small (3-mm OD) Bergstrom biopsy needle. The
biopsies weighed 8-14 mg and contained 100-200 fibers, of which an average
of 40 fibers were acceptable for metabolic and size analyses. The 14-day
spaceflight had little effect on fiber size in the Sol and MG muscles,
whereas there appeared to be a slight decrease in size in the TA. In each
of the flight animals, the mean fiber size in the postflight biopsies
increased relative to preflight values. An increase in fiber size over the
same period of time was also observed in four control monkeys that were the
same age and approximately the same weight as the flight monkeys. The
relative increase in size was related to the body weight of the monkey at
the time of the pre- and postflight biopsies. The mean fiber succinate
dehydrogenase activity appeared to decrease in the MG, whereas there was no
apparent effect of spaceflight on the Sol and TA muscles.(ABSTRACT
TRUNCATED AT 250 WORDS)
