Aug. 3 (HealthDay News) -- In a finding that is a major advance in spinal cord injury research, U.S. scientists report that regenerating axons can be guided to their correct targets where they can re-form connections after spinal cord injury.

Previous research showed that severed axons -- long, slender projections of a nerve cell that conduct electrical impulses -- can be coaxed to regenerate into and beyond sites of spinal cord injury. But it hasn't been clear how to guide these axons to the precise target, according to a news release from the University of California, San Diego.

In experiments on rats, researchers at the UCSD School of Medicine found that regenerating axons can be guided to the correct target using a nervous system growth factor called neurotrophin-3 (NT-3).

When the growth hormone was placed in the correct target, axons grew into it and formed electrical connections called synapses. When the growth factor was placed in the wrong target, the researchers found that the axons grew into that target as well, according to the study published online Aug. 2 in the journal Nature Neuroscience.

"The ability to guide regenerating axons to a correct target after spinal cord injury has always been a point of crucial importance in contemplating translation of regeneration therapies to humans," senior author Dr. Mark Tuszynski, director of UCSD's Center for Neural Repair, said in a news release.

"While our findings are very encouraging in this respect, they also highlight the complexity of restoring function in the injured spinal cord," he said.

SOURCE: University of California, San Diego, news release, Aug. 2, 2009