Genetically modified “super mice” that NASA sent with SpaceX to the International Space Station returned to Earth. Experiments on mice may be a cure for astronauts who suffer muscle and bone loss during their task. The mice, provided by the nonprofit Jackson Laboratory in Maine, were genetically manipulated for muscle growth in an experiment to better understand how zero gravity affects the human body. The mice weren’t there on vacation, of course, but were part of an experiment to test how muscles are impacted by the microgravity environment of the space station. These so-called “Mighty Mice” were genetically modified to have enhanced muscle growth, which scientists believed would help them study the effects of microgravity on their muscles and bone structure. According to NASA, the experiment was called Rodent Research-19 and was used to study myostatin and activity, signaling pathways that may affect muscle destruction. Researchers believe that these molecules can be used to prevent muscle and bone loss during astronaut’s missions and to help them recover after returning to Earth. The findings may also help to develop treatments for other patients with muscle and bone loss worldwide. At the space station, mice received treatment that inhibited signal transduction pathways to see how it affects bone and muscle losses. Prevention of these pathways is known to induce muscle and bone growth. Mice are genetically engineered for myostatin deficiency and have twice the muscle mass of an average mouse. 40 female mice from the space station will be compared to the control group of the remaining 40 female mice on Earth. The findings can also be applied to long-term space missions to be carried out on the Moon and Mars in the future. Now that the “mighty mice” and their companions are back on Earth, researchers can study the rodents, looking for ways to manipulate myostatin to address human muscle and bone loss. “The knowledge we gain about microgravity’s effects on muscles and bones will help us to enhance the health of astronauts – both in space and on Earth,” researcher Se-Jin Lee said in a press release, “and also better understand the promise that myostatin inhibitors hold for the elderly, people who are bedridden, and for people experiencing muscle-wasting related to diseases like AIDS, ALS, cancer, and so many others.”