How fishes will help futur astronauts in space

by Tachim on September 16, 2017 - 6:08pm

On September 14th 2017, Melissa Gaskill who is working at the International Space Station Program Office, wrote an article about how transparent fish called Medaka could help researchers find a solution to the bone density loss of astronauts. This phenomenon is due to the fact that in microgravity, the body does not work as much as when he is on earth. This causes the bone mass to decrease due to insufficient work. To prevent too much bone mass loss, the astronauts need to exercises at least two hours per day and have weeks of rehabilitation.

Now, why use Medaka fish for this experiments? Simply because their transparency helps the researchers target what they are looking for. Secondly the osteoclasts molecular structures are shown to have no major differences between the mamal and the fish, which made these little fishes even more suitable for this experiment.

In order to understand the mechanism behind osteoclasts, a cell that breaks the bone cells in order for them to get replaced, they sent those transparent Medaka fish (or japanese rice fish) into space with a little change in their DNA. In fact they attached a fluorescent protein to the osteoclasts and the osteoblasts, a cell that is responsible for the synthesis of the bone during the formation and the remodeling, in order to observe mollecular and genetic changes in the fish during the flight. Akira Kudo, principal investigator for this study at the Tokyo Institute of Technology, was surprised by the results they got. In fact, the fluorescent signals sent by the osteoclasts and the osteoblasts were significantly higher than the ones on earth. These results can be explained in part because the bones (mineralized tissue) are more affected by gravity since they are denser than any other tissue in the body.

However, scientists have found more from this experiment. They have identified five genes that are related to how the cells react to gravity. Those five genes all closely related to glucocorticoid receptors in the mitochondria in the cells. Glucocorticoid is a type of steroid that are responsible of the metabolism of glucose and glucocorticoid receptors potentially play a role in the osteoclasts activation. While the results are not clear again as to why the receptors play a role  during space flight, more research need to be done specifically for this purpose.

The results could help scientists find ways to stop bone mass loss as well as help other problems in real life scale. It could help develop drugs and treatments for people having this disease caused by bed-rest, limited mobility or aged-related osteoporosis.

If you want to read more about this article: https://www.nasa.gov/mission_pages/station/research/news/medaka_osteoclast2

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