BEIJING, June 5 (Xinhua) -- The taikonauts of Shenzhou-15 (Divine Vessel) achieved many notable firsts during their 186-day space trip, one of which was undertaking scientific research on the production of early-stage human blood cells aboard the orbiting Chinese space station.
After the cargo craft Tianzhou-6, or "Heavenly Vessel," docked with the Tiangong space station in May, the Shenzhou-15 taikonauts assisted the science team on-site to perform six to 15 days of cell culture experiments in orbit.
The experiments involved the use of pluripotent stem cells, which have the capacity to self-renew and maintain the potential to develop into other types of cells. They are an excellent cell source for regenerative medicine, which focuses on regenerating human cells, tissues and organs to restore normal functions damaged by aging, disease or accident.
Before returning to Earth, the Shenzhou-15 crew conducted an experiment to differentiate cobble-like hematopoietic stem cells, which can produce blood cells.
These stem cells have grown mature and differentiated into a group of blood stem cells resembling a bunch of grapes, said Lei Xiaohua, a member of the experiment's design team, at the Shenzhen Institute of Advanced Technology under the Chinese Academy of Sciences.
"We have achieved our first experimental goal: For the first time, blood cells have been generated in vitro from human embryonic stem cells in space," Lei told media.
In 2017, Chinese scientists carried out research on the proliferation and differentiation of mouse embryonic stem cells on the Tianzhou-1 cargo craft. The results showed that stem cells cultured in space showed better 3D growth than those on the ground and maintained higher levels of pluripotent gene expression.
Foreign scientists have also conducted research on stem cell growth and tissue regeneration during spaceflights in recent years, including research on blood stem cells for astronauts suffering from anemia, indicating that in-orbit experiments can be used to explore how microgravity improves human health, Lei said.
Three taikonauts brought the cells back to Earth aboard the Shenzhou-15 spaceship on Sunday.
Lei said his team will compare the cells produced in space with cells on Earth, in an attempt to screen out the genes that affect early blood cell differentiation in the space environment.
Researchers will continue to conduct experiments on the 3D growth of stem cells during the future Tianzhou-7 and Tianzhou-8 cargo missions.
One of the functions of China's manned space program is to search for possible habitable planets, said Cang Huaixing, chief researcher for the station's scientific experiments, at the Technology and Engineering Center for Space Utilization under CAS.
"The space environment has microgravity and high radiation, so how to travel, survive and have children in such an environment is the main task in our research," Cang said in an interview with Xinhua.
