Among the challenges of medicine, spinal cord injury ranks high. Nerve cells in the spine don't regenerate naturally, and attempts to revive or repair a damaged cord have met with frustration. To bypass this problem, researchers have recently tried animal experiments replacing ruined nerve cells in animals with transplants of fetal cells. This technique has shown promise, but only when experimenters perform the transplant within a few days of an injury.
Researchers at Washington University School of Medicine in St. Louis now report that they have restored leg movement in injured rats by transplanting cells into the injury site 9 days after the rats received a crushing blow to the spine. The scientists used mouse-embryo stem cells modified to ensure they would grow into basic nerve cells and associated cells.