Stem Cell Injections Give Mice Mighty Muscles

Injecting stem cells into injured mouse muscle not only helped the muscle heal, but gave the mice enhanced muscle mass for years to come. The study, published in Science Translational Medicine, used skeletal muscle stem cells from young donor mice and injected them into injured muscles of mature mice. Researchers figured that the stem cells would be able to create new muscle cells in the recipient mouse, but the question was: could these new cells be incorporated into the existing muscle on an adult mouse? After injuring the recipient mouse's muscle and injecting the cells, the researchers noticed that the injury healed quickly and the mice had larger muscles (about twice the volume, and a 50 percent increase in mass) than before the injury, which they expected. But were surprised to see that the muscle enhancement was sustained throughout the recipient mouse's lifetime, up to two years.