Anabolic steroids are against the rules for professional athletes, but preliminary research suggests that steroids may help repair a shoulder injury that affects many professional and weekend athletes.

In lab experiments using bioengineered tendons, researchers at the University of North Carolina at Chapel Hill found that tendons treated with an anabolic steroid were stronger than untreated tendons.

“In a highly experimental model, anabolic steroids do appear to improve the quality of rotator cuff tendon tissue,” lead author Dr. Spero G. Karas told Reuters Health.

Most likely, steroids help by improving protein production in each tendon cell or by boosting the way tendon cells communicate with each other, Karas said.

But don’t expect doctors to start prescribing anabolic steroids to people who have rotator cuff surgery any time soon. Karas cautioned that much more testing needs to be done.

“If enough testing can conclude that this treatment is effective, then of course we could attempt it in humans with difficult rotator cuff injuries,” Karas said.

The rotator cuff is made up of the muscles and tendons that hold the upper arm bone to the shoulder. When the rotator cuff is injured, surgery may be performed to repair it. Unfortunately, healing after surgery is often incomplete and many people experience repeat rotator cuff injuries.

Anabolic steroids are known to build muscle mass and boost strength, so Karas and his colleagues set out to see whether steroids might improve rotator cuff healing.

The research involved bioengineered tendons developed by co-author Dr. Albert J. Banes. The researchers collected tendon samples from six people who were having rotator cuff surgery. Cells from these tendons were isolated and used to grow the bioengineered tendons.

Some of these tendons were treated with the anabolic steroid nandrolone decanoate, while others were not. Some tendons were also subjected to load testing, in which the tendons were stretched.

Tendons that had been treated with steroids and subjected to loading were stronger, denser and more elastic than other tendons, the researchers report in the American Journal of Sports Medicine. The steroid-treated tendons also had a more natural appearance than other tendons.

The research will not have an immediate impact on the treatment of rotator cuff injuries, but the research establishes a way to test the effect of mechanical stress and medications on tendon cells, Karas said.

“Any drug can be tested, but we chose an anabolic agent because of its successful background in treating patients with burns and other injuries,” Karas said.

Another potential implication of the research, according to Karas, is that it “may permit us to manufacture a matrix of tissue that can be used to replace deficient human tissues.”

Karas noted, “We are only in the embryonic phases of this work. We are a long way off, but the potential is exciting.”

SOURCE: American Journal of Sports Medicine, June 2004.