A treatment that encourages injured nerve fibers to regrow helped rats recover from spinal cord injury, a finding described as a modest but significant step in developing new treatments for people.
The treatment was aimed at proteins in the brain and spinal cord that normally suppress regrowth of nerve fibers after injury. The rats were treated with antibodies designed to disable these proteins and therefore remove the brake on regrowth.Scientists cut a bit more than halfway through the spinal cords of 61 rats. Twenty-three of the rats were treated, starting at the time of the injury.
The injury initially paralyzed the back legs on the side of the cut. All the animals eventually regained some ability, but the treated rats recovered more than the other rats did.
The work is reported in Thursday's issue of the journal Nature by Barbara Bregman of the Georgetown University Medical Center in Washington, D.C., with scientists there and at the University of Zurich.
The spinal injury shortened the steps the animals took with their affected legs. But treated rats took longer steps with their affected legs than untreated animals did, bringing their steps much closer to the lengths seen in healthy animals, Bregman said.
Most of the treated rats also recovered a leg reflex that requires signals from the brain, while none of the untreated ones did.
The treated animals also showed more nerve fibers growing in a detour path around the injury site than untreated animals showed. Some of those fibers may have come from nerve cells in the undamaged part of the spinal cord, Bregman said.
Bregman cautioned that people should not get false hopes from the results. It's not clear such treatment will be useful in people, and if it is, the benefit will be years away, she said.
Dr. Richard Bunge, scientific director of the Miami Project to Cure Paralysis, a unit of the University of Miami School of Medicine, called the work a modest but significant advance.