China's "Fish Astronauts" to Study Space's Impact on Vertebrates

China's "Fish Astronauts" to Embark on Another Space Journey

Following the success of China's first "space fish farming" experiment, the "fish astronauts" are set to embark on another journey to the Tiangong Space Station this year. This mission aims to help scientists study the effects of the space environment on vertebrate muscle and bone development.

The "fish astronauts" are small tropical freshwater zebrafish, which share over 70% of their genome with humans. This makes them a crucial model organism for research in various fields, including life sciences, health sciences, and environmental sciences. In April 2024, the "Tiangong Aquarium" containing four zebrafish and four grams of hornwort was sent to China's space station aboard the Shenzhou-18 spacecraft. This marked the first successful establishment of an in-orbit self-sustaining aquatic ecosystem in China.

Scientists were able to simulate the material cycle of the biosphere through the zebrafish and hornwort, enabling gas balance and long-term stability of the aquatic ecosystem. The ecosystem operated stably for 43 days, setting a world record for the longest in-orbit operation of a space aquatic ecosystem.

The success of the first mission demonstrated that China's in-orbit self-circulating aquatic ecosystem can serve as a platform for zebrafish to assist scientists in space health research. The second mission, planned for this year, will include six zebrafish and six grams of hornwort. Through the zebrafish, scientists will focus on studying the impact of microgravity on the proteins of vertebrate muscles and bones.

Microgravity in space leads to various pathophysiological changes in the human body, such as cardiovascular dysfunction, decreased immune function, bone loss, muscle atrophy, and endocrine disorders. Studying zebrafish in space will help humans gain a more comprehensive understanding of how the space environment affects genes, cells, and entire organisms. This knowledge will be invaluable for future space exploration.