WASHINGTON (CNN) -- Researchers from the University of Pennsylvania have developed a new gene therapy treatment that seems to permanently block age-related muscle loss in mice. These findings were presented Monday at an annual meeting of the American Society of Cell Biology in San Francisco.

Researchers found the treatment, when used in older mice, increased muscle strength by 27 percent over untreated muscle and in young adult mice there was a 15 percent increase in muscle. The muscle size and strength in the older treated mice were found to be undistinguishable for those of the young untreated adult mice.

In mice, the treatment is delivered through a one time injection directly into the muscle. It works by enabling the muscle to repair itself more efficently.

Senior investigator H. Lee Sweeney suggests this treatment could potentially be used in humans to reverse the muscle loss of size and strength related to age or to counteract the muscle-wasting effects of certain diseases, such as a type of muscular dystrophy.

Sweeney also warns of the possible ethical concerns in the use and possible abuse in athletic or cosmetic enhancement.

According to researchers, all mammals lose up to one third of their muscle mass and strength with age. They point out that in humans this can result in impaired mobility, unsteadiness and increased susceptibility to falls and injury.

Sweeney says more mice studies are underway to examine the effects of the treatment when done in combination with exercise. Human trials on muscular dystrophy patients could begin shortly thereafter.

The study was funded by the National Institutes of Health and the Muscular Dystrophy Association.