New York City ? Scientists eased symptoms of muscular dystrophy in mice by injecting modified stem cells from human patients, a preliminary result that raises hopes for treating patients with tissue from their own bodies.

The mice showed stronger muscles and ran longer on a treadmill than diseased mice that weren’t treated.

Other experimental treatments for muscular dystrophy have also produced encouraging results in lab animals. Last year, for example, scientists reported improvements in golden retrievers that had received stem cells from other dogs.

The new study involved not only using stem cells, but also modifying those cells to affect how they read their DNA.

The paper focused on Duchenne muscular dystrophy, a muscle-wasting genetic disorder appearing in boys that occurs in about 1 in every 3,500 male births. It’s the most severe and most common childhood form of muscular dystrophy.

Boys with Duchenne dystrophy have trouble walking as early as preschool, and nearly all of them lose their ability to walk between ages 7 and 12.