A Laser Fusion Rocket based on Fast Ignition Concept
- Paper number
IAC-05-C3.5-C4.7.07
- Author
Dr. Hideki Nakashima, Kyushu University, Japan
- Coauthor
Dr. Yoshihiro Kajimura, Kyushu University, Japan
- Coauthor
Yasuji Kozaki, Osaka University, Japan
- Coauthor
Dr. Yuri Zakharov, Russia
- Year
2005
- Abstract
Exposure to microgravity induces degeneration in the musculoskeletal system including fiber atrophy and shift of fiber types from slow to fast in skeletal muscles and decrease in bone density. Hyperbaric exposure with high oxygen concentration enhances the partial pressure of oxygen and dissolves more oxygen into blood and plasma. The increased oxygen enhances the oxidative metabolism in cells of peripheral tissues and therefore would improve degeneration in the musculoskeletal system. This study investigated effects of hyperbaric exposure with high oxygen concentration on unloading-induced degeneration in the musculoskeletal system. Ten–week-old male mice were subjected to hindlimb suspension for two weeks. Thereafter, those mice were recovered with or without hyperbaric exposure for two weeks. The mice were exposed to an atmospheric pressure of 1.25 with an oxygen concentration of 36% for 6 h a day. Body and muscle weights, fiber cross-sectional areas and oxidative enzyme activities in the deep and surface regions of the tibialis anterior muscle, and cortical and trabecular densities of the femur bone were investigated. Serial transverse sections, 10-µm thick, of the muscle were cut in a cryostat. The sections were brought to room temperature, air-dried for 30 min, and stained for succinate dehydrogenase activity, an indicator of mitochondrial oxidative capacity. The femur bone was analyzed using peripheral quantitative computed tomography. Unloading-induced decreases in the body and muscle weights were recovered with and without hyperbaric exposure with high oxygen concentration. There was no change in the fiber cross-sectional area in the deep or surface region by unloading or hyperbaric exposure with high oxygen concentration. Unloading-induced decreased fiber oxidative enzyme activities in the deep and surface regions and cortical and trabecular bone densities were recovered by hyperbaric exposure with high oxygen concentration. These results indicate that unloading induces musculoskeletal degeneration including decreased fiber oxidative enzyme activity and bone density in mice and that hyperbaric exposure with high oxygenation concentration is effective for musculoskeletal regeneration.
- Abstract document
- Manuscript document
IAC-05-C3.5-C4.7.07.pdf (🔒 authorized access only).
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