The diseases cause muscle weakness and wasting
Transplanting adult stem cells into mice with an illness like muscular dystrophy (MD) helped rebuild muscle structure and strength, a study says.
The work by Harvard University, published in the journal Cell, boosts the prospect of similar treatments for people with the condition one day.
There is no cure for the disease, which is inherited and causes rapid and progressive weakening of muscle tissue.
About 1 in every 20,000 births in the
UK are affected by muscular dystrophy.
The idea behind stem cell therapy is to find a way to boost the body's ability to replace or produce new tissues.
Stem cells can have the ability to form a wide variety of tissue types, and the Harvard team focused on adult muscle stem cells, which specialise in generating new muscle cells in response to growth or injury.
They bred mice which have a faulty dystrophin gene, the same problem which causes Duchenne MD in humans.
They then took adult muscle stem cells from other mice and injected them into the diseased mice's muscles.
One of the challenges in this approach is finding the correct cells, but the researchers developed a way to identify them using particular proteins found on their surface.
Once the stem cells were in place, they spread throughout the muscle, producing new cells and improved the way it worked.
They also persisted in the stem cell form in a "reservoir", suggesting they could offer a longer-term benefit.
Dr Amy Wagers, who led the project, said: "This study indicates the presence of renewing muscle stem cells in adult skeletal muscle, and demonstrates the potential benefit of stem cell therapy for the treatment of muscle degenerative diseases such as muscular dystrophy."
She said that as well as offering a potential treatment in humans, understanding how the stem cells worked could help produce other therapies to boost the process in humans.
One of the problems of using adults stem cells from a donor would be the possibility of immune system rejection, but, in mice at least, the technique did not require the recipient's immune system to be suppressed.
However, Dr Wagers said that one obstacle to using the cells in MD was finding a way to distribute the cells to every affected muscle throughout the body.