Experiment

"Effect of microgravity on osteoclasts and the analysis of the gravity sensing system in medaka (Medaka osteoclast)" experiment has been completed

A life science experiment "Effect of microgravity on osteoclasts and the analysis of the gravity sensing system in medaka* (Medaka osteoclast)," which uses the Aquatic Habitat (AQH) has been completed on board Kibo, the Japanese Experiment Module.

*Principal Investigator (PI) Akira Kudo
Professor, Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology.

Medaka osteoclast experiment was performed for about two months, from Friday, October 26, 2012, to Monday, December 24, 8:23 p.m.

The medaka osteoclast experiment consists of two kinds of experiments. The first experiment conducted this time is a long-term culture experiment which keeps young medaka fish or killifish (Oryzias latipes) for two months. At certain periods after the experiment start, some medakas were sampled from the Aquatic Habitat (AQH) aquariums and chemically fixed*. In addition, at the start and end of the culture, medaka genes were treated for preservation. Obtained samples were returned to the Earth to analyze the structure and gene expression of tissues and cells surrounding medakas' teeth and bones.

*Chemical fixation: One of the fixation methods for biological samples and is a chemical process by which cells, protein, and lipid in structures are preserved using a fixing agent such as paraformaldehyde.

The second experiment is to launch transgenic embryo and juvenile medakas whose osteoclast or osteoblast cells specifically become fluorescent and to perform on-orbit, short-term observation of such cells. This experiment is scheduled for the next Japanese fiscal year.

By studying the osteoclast cells of medaka fish in microgravity, discovery of a novel mechanism of absorbing bones may be possible. The results are expected to be a start of the development of a new treatment for senile osteoporosis, of which a loss of cortical bone mass is seen.

【Remarks from the PI, Prof. Kudo, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology】

Thanks to JAXA, and other all related parties, as well as astronauts Hoshide and Ford, medakas were able to live in space for two months.

Some medakas who lived for two weeks in space have already returned to Earth aboard the Soyuz spacecraft* and the analysis has already been started. We need another one year to see all the results and look forward to see what we find from them.

* Soyuz TMA-05M (31S) spacecraft

*All times are Japan Standard Time (JST)