Once damaged, nerves in the spinal cord normally cannot grow back and the only drug approved for treating these injuries does not enable nerve regrowth.

Publishing online this week in the Early Edition of the Proceedings of the National Academy of Sciences, researchers at the Johns Hopkins University School of Medicine show that treating injured rat spinal cords with an enzyme, sialidase, improves nerve regrowth, motor recovery and nervous system function.

Sialidase is a bacterial enzyme that removes specific chemical groups found on the surface of nerve cells. The chemical groups normally function to stablize the cells, but also act to prevent nerve regeneration.

The team built upon earlier research where they disovered that sialidase treatment improved the growth of nerves into a graft. "We wanted to take this further and look at the animal model most relevant to human spinal cord injury," says Schnaar.

"Typically, in motor vehicle accidents for example, vertebra shift and pinch the spinal cord, severing the long spinal nerve axons like you would if you pinched a piece of wet spaghetti." So they treated rats after a spinal cord impact injury by injecting sialidase directly to the injury site.

Rats with lower-back impact injury - severe enough to lose hind-limb function - were injected with sialidase directly over the spinal cord immediately following injury. The researchers then implanted into each rat a small pump that delivered a steady stream of sialidase directly to the injury over the course of two weeks, hoping that bathing the injured nerves in the enzyme would help their recovery and promote regrowth.

Source: Johns Hopkins Medical Institutions