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  5. Effect of microgravity on osteoclasts and the analysis of the gravity sensing system in medaka
2021.02.26
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[Medaka Osteoclast]
Effect of microgravity on osteoclasts and the analysis of the gravity sensing system in medaka

  • Biology and Biotechnology
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ISS Science for Everyone

SCIENCE OBJECTIVES FOR EVERYONE

Enhancement of the osteoclast (bone resorption cell) is assumed to cause the decrease of bone mineral density in space. Medaka fish is a model animal for the life science research, and JAXA plans to study the effects of microgravity on the osteoclast activity and the gravity sensing system of the vertebulate using Medaka fish on board the Kibo Module.

SCIENCE RESULTS FOR EVERYONE

Chew on these results. Jaw bones of Japanese medaka fish in microgravity show decreased mineral density and increased volume of osteoclasts, cells that break down bone tissue. Some genetic changes in tissue from the brain, eye, liver, and intestine were seen in the space fish. However, the intestine appeared to be most sensitive to microgravity. No significant gene changes were detected in ovaries or testes. Microgravity slightly disrupted egg creation in these fish but there was no delay in body growth and maturation. These results improve understanding of the mechanisms behind bone density and organ tissue changes in space.

Experiment Description

RESEARCH OVERVIEW

  • During the space flight, bone mineral density is decreased by the influence of osteoclast activation, which molecular mechanism is expectantly investigated. To find the effect of microgravity on osteoclast in space, we perform a long-term experiment with small fresh water fish, medaka, and examine the alteration of osteoclast activity under microgravity with the histological analysis or the gene expression analysis by RNA in-situ hybridization.
  • Medaka will be launched by SpaceX-2 and 2months experiment will be started using the Aquatic Habitat. After approx. 2weeks, 1month, and 2months from the experiment start, medaka will be sampled from the Aquatic Habitat Aquariums and chemically fixed for the retrieval. Also, the Aquatic Habitat maintenance operations, such as water sampling, water quality check, water exchange, and ORU exchanges are planned.
  • Fixed samples will be retrieved by SpaceX-2 and SpaceX-3.

Media Gallery

Aquarium holding the Medaka Osteoclast ground testing (JAXA)

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PRINCIPAL INVESTIGATOR(S)

KUDO Akira [Tokyo Institute of Technology]

JAXA’s Utilization Themes List

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