Tianzhou 1 to test bone-loss medicine
During the maiden voyage of Tianzhou 1, China’s first cargo spacecraft, scientists will test a medicine for treating bone loss that was developed for astronauts but which they hope will benefit ordinary people.
The main mission of Tianzhou 1, which was launched on Thursday, is to test propellant refueling technology, which is crucial for the construction and operation of China’s planned space station. However, each voyage presents a precious opportunity to conduct space experiments.
Chinese scientists will use the microgravity environment to test the role of an acid known as 3HB (for 3-hydroxybutyric acid) in preventing osteoporosis, according to research leader Chen Guoqiang, who is also director of Tsinghua University’s Center for Synthetic and Systems Biology.
Normally, the solid structure of bone tissue is stimulated and maintained by gravity and physical exercise. However, the microgravity environment of space eases the load, causing rapid bone loss and osteoporosis, Chen said.
“One day of bone loss in space is equivalent to a year on Earth,” he added.
Research shows astronauts suffer average monthly bone loss of 0.5 to 2 percent in space, especially in weightbearing bones such as the tibia, femur and vertebrae.
Back on Earth, they can take double or triple the time of their flight period to recover. Sometimes bone loss is permanent.
Microgravity mainly inhibits the differentiation of osteoblasts (bone-forming cells), which is accompanied by the mass growth of osteoclasts (bone-resorbing cells), causing bone structure to change, Chen said.
Standard drug treatments for osteoporosis have a range of side effects, including tumors or cardiovascular disease. The medicines are also relatively ineffective for treating osteoporosis caused by microgravity.
Chen said 3HB is one of the main components of ketone bodies — chemicals the body makes to compensate for a shortage of insulin in the blood for breaking down sugar. It occurs naturally in mammals and has been used to treat epilepsy for many years.
“We found that 3HB can promote bone formation,” he said, adding that in an experiment simulating a microgravity environment, the effect was obvious.
Unlike the chemical synthetic 3HB for treating epilepsy, Chen’s team uses microbial fermentation to produce 3HB, which has the same structure as the 3HB naturally existing in the human body. So it’s safer than chemical synthetic drugs, Chen said.
Experiments simulating a microgravity environment have been conducted on Earth. Scientists hung up mice by their hind legs, and found that those given 3HB had normal bones, while others suffered serious bone loss.
“We hope to test the effect of the medicine in a real microgravity environment in space,” Chen said.
As Tianzhou 1 cannot carry animals, scientists will compare the osteoblast cell samples that are treated to those not treated with 3HB. Microscope images of the samples will be transmitted to Earth.
Although China has conducted many experiments in the Shenzhou series of spacecraft, as well as in the Tiangong I and Tiangong II space labs, opportunities for space experiments remain rare.
“After more than a decade of research, we have one chance to conduct an experiment in space. We cherish the chance and hope Chinese scientists will have more opportunities to conduct experiments in China’s space station in the future,” Chen said.
Scientists believe the knowledge developed in space exploration can benefit ordinary people. For instance, modern baby diapers were originally developed for astronauts on extended spacewalks. The intensive care unit system in hospitals was first developed to monitor astronauts preparing to go to the moon in the 1970s.