- 著者
- Natsuhiro Takahashi Masamichi Takami Masahiro Chatani
- 出版者
- Japanese Society for Biological Sciences in Space
- 雑誌
- Biological Sciences in Space (ISSN:09149201)
- 巻号頁・発行日
- vol.35, pp.24-31, 2021 (Released:2021-09-01)
- 参考文献数
- 18
Bones are important organs for body resistance against force produced by gravity, though the influence of gravity on bone development is unclear. To examine the effects of gravity on osteogenesis, medaka larvae were reared in water or gel under various conditions. For determining the effects on bone development in a state of motion, larvae were reared in water under normal gravity (1g) or hypergravity (5g) conditions. Also, to examine the direct effect of gravity on bone mineralization, larvae were embedded in low melting agarose gel containing alizarin complexone (ALC) and reared for three days under a normal gravity (1g), simulated-microgravity (s-μg) with use of a clinostat device, or 5g condition. Medaka reared in water under the 5g condition showed forward protruding jaws and spreading of the mineralized area of jaw teeth as compared to those reared under the 1g control condition. In addition, the direction of growth of the notochord in the fin region was changed upward in those reared under the 5g condition, accompanied by a part of acetylated tubulin-positive nerves also localized upward, while positive signals for DsRed, expressed by an osterix promoter, in osteoblasts were increased in the fin region. On the other hand, in medaka reared in gel, ALC signals in the fin ray of those in the s-μg condition were increased as compared to those in the 5g condition. Changes noted in medaka larvae over three days indicated osteogenesis adaptation to the specific gravity environment. The present results obtained with an experimental system are considered useful for examinations in the future regarding changes of osteogenesis, which will be needed to clarify the mechanism of the effects of gravity on bone development.
- 著者
- Masahiro Chatani Aiko Mitsuhashi Yusuke Dodo Nobuhiro Sakai Masamichi Takami
- 出版者
- Japanese Society for Biological Sciences in Space
- 雑誌
- Biological Sciences in Space (ISSN:09149201)
- 巻号頁・発行日
- vol.33, pp.12-17, 2019 (Released:2019-09-10)
- 参考文献数
- 18
- 被引用文献数
- 3
Teleost fish live under a constant force derived from gravity, with hard tissues playing important roles to help maintain body balance. However, the mechanism of hard tissue formation induced by gravity remains unclear. To examine the effects of gravity in aquatic animals, we performed experiments with medaka fish reared in a hypergravity environment, in which the force of gravity exceeded that present on the surface of the Earth, and analyzed hard tissue formation. Medaka fish were reared for 6 months under a normal gravitational force (1G) or that 5.29 times greater than normal (5.29G) using a centrifuge designated for small fish rearing. Micro-CT analysis results showed that hypergravity induced a vertebral curvature towards the dorsal side and asymmetric formation of otoliths in which the cross-sectional area was increased. Our findings indicate that the process of adaptation to a hypergravity environment results in spinal and otolith deformation in medaka fish.