Fish Are Having a Real Hard Time in Space

Fish traveling aboard the International Space Station in 2014 experienced a near-immediate reduction in bone density upon encountering the microgravity environment of orbit. This is according to research published recently in Scientific Reports by a team of biologists at Tokyo Institute of Technology who conducted remote imaging experiments on newly-hatched medaka fish launched into space.

By Michael Byrne | MOTHERBOARD

The general findings are concerning but not all that surprising. The dramatic effects of microgravity on bone density have been observed in human astronauts aboard the ISS, where bone deterioration begins after about 20 days in orbit in a process resembling the sort of osteoporosis more often associated with old age. The mechanisms behind this, however, are still being explored, both for the sake of long-term space travel and for treating osteoporosis here on Earth’s surface. And so we have medaka fish, whose process of skeletogenesis is similar to our own.

„Under microgravity, there are several changes in the animal body, such as fluid shift, increase in blood pressure, and dizziness,“ Akira Kudo, the study’s lead author, and colleagues explain. „In particular, bone mineral density is decreased under microgravity; but it is unclear how osteoblasts or osteoclasts respond early in orbit.“

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