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Gravity and Skeletal Growth: IV. Intervertebral Disc Swelling Pressure Associated with Microgravity (COS 1887-13)
Research Area:
Bone and calcium physiology
Species Studied
Scientific Name: Rattus norvegicus Species: Rat Strain: Wistar


The back pain experienced by space travelers during exposure to microgravity may be caused by spinal lengthening due to swelling of their discs, a subsequent stretching of anterior and/or posterior spinal ligaments. Other work has documented that pooling of lumbar discs from the rat spine allows sufficient disc material for direct measurements of swelling pressure in this species. Therefore, studies of Cosmos 1887 rats allowed testing of the hypothesis that microgravity causes fluid uptake and decreased swelling pressure within the intervertebral disc of flight rats compared to ground-based, control rats.

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Glover, M.G. et al.: A New Technique for the in vitro Measurement of Nucleus Pulposus Swelling Pressure. Journal of Orthopedic Research, vol. 9, 1991, pp. 61-67.

Hargens, A.R. and M. Mahmod: Decreased Swelling Pressure of Rat Nucleus Pulposus Associated with Simulated Weightlessness. Physiologist, supl., vol. 32, no. 1, 1989, pp. S23-S24.

Hargens, A.R. et al.: IV. Intervertebral Disc Swelling Pressure Associated with Microgravity. Final Reports of the U.S. Experiments Flown on the Soviet Biosatellite Cosmos 1887. J.P. Connolly, R.E. Grindeland, and R.W. Ballard, eds., NASA TM-102254, 1990, pp. 147-149.

Murthy, G. and A.R. Hargens: Intervertebral Disc Swelling Pressures in Normal Gravity and Microgravity (abstract). American Society for Gravitational and Space Biology Bulletin, vol. 6, no. 1, 1992, p. 88.

Cerebrospinal fluid
Intervertebral disk
Spinal diseases
Back pain

Data Information
Data Availability
Archive is complete. No data sets are available for this experiment. Please Contact LSDA if you know of available data for this investigation.

Fluid shift, Spinal cord, rat
Morphology, Nucleus pulposus, intervertebral disc, spine, rat, Light microscopy (descriptive)
Pressure, swelling, Nucleus pulposus, (vertebrae disk), rat, Compression-type osmometer (mm mercury)
Size, Intervertebral disc, rat

Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Cosmos 1887 09/29/1987 10/11/1987 13 days

Additional Information
Managing NASA Center
Ames Research Center (ARC)
Responsible NASA Representative
Ames Research Center LSDA Level 3
Project Manager: Martha Del Alto
Institutional Support
National Aeronautics and Space Administration (NASA)
Alternate Experiment Name
Protocol / Approach
Hardware Items