5 Basal, 5 Vivarium, 5 Synchronous,5 Tail-Suspended
Key Flight Hardware
Cosmos 2044 Russian Hardware Suite
Objectives/Hypothesis
Experiments flown on Cosmos 1887 were complicated by unexpected postflight processing
delays. To differentiate between flight response with minimal recov- ery time
and flight response with extended recovery superimposed, this experi- ment was
repeated with the addition of a tail-suspended model as a control group. Data
from this study are difficult to compare with that from Cosmos 1887 due to a
25-day age difference; the larger bones of these animals agree with the older
age of the rats.
Approach or Method
Bone area and perimeter were measured at the tibiofibular junction of space-flown
and ground control rats. Bone vascularity and bone cells within the tibial diaphy-
sis, and collagen fibrils in the tendons of the foot were studied at the light
and electron microscope level. The portion of the tibial shaft immediately proximal
to the tibiofibular junction was sawed into 50 µm cross-sections, mounted on
slides, and exposed to incident and polarized light.
Results
Visual observations of tibial cross-sections under brightfield or polarized
light did not show any obvious differences. Likewise, area and periosteal perimeter
meas- urements showed no significant differences. The lack of any increase in
bone mass during the flight period indicates that animals were adults; thus
bone mass was not accumulating rapidly during the flight period. Larger, adult
rats may require a longer flight period to demonstrate bone changes, particularly
in cortical bone since the skeleton is turning over more slowly.
Publications
Experiment Reference Number: C2044-9.1
Morey-Holton, E.R.: Gravity and Skeletal Growth: I. Gravity and Skeletal Growth.
Final Reports of the U.S. Experiments Flown on the Soviet Biosatellite Cosmos
2044. Vol. 1. J.P. Connolly, R.E. Grindeland, and R.W. Ballard, eds., NASA TM-108802,
1994, pp. 189-192.
¥ = publication of related ground-based study