BOSTON (Reuters) - A nerve growth factor, Inosine, stimulated regrowth of severed spinal cord motor nerve fibers in an experiment on laboratory rats, Boston Life Sciences Inc. said on Friday.

The company said the regrowth was being accomplished experimentally for the first time and could bring Inosine, which occurs naturally in the body, closer to human trials.

In the experiment, Inosine was administered to rats with severed spinal cords. In four of the five treated rats, new fibers were seen coursing through the injury to reestablish connections, the company said.

Dr. Marc Lanser, the chief scientific officer of the company, said in a statement that he hoped to submit the results for publication shortly. "This represents a giant step forward in our spinal cord program since these results indicated that motor function can potentially be reestablished under the control of the same area of the brain that gave rise to the injured spinal cord fibers," he said.

In an experiment published in the Proceedings of the National Academy of Sciences late last year, an experiment showed cross-over sprouting of motor axons, a part of a nerve cell, in injured spinal cords, the company said.

Boston Life planned to duplicate the results of the experiment in primates before starting human clinical trials.

Boston Life Sciences has been developing Inosine and another nerve growth factor, AF-1, for regenerative treatment of spinal cord injuries and stroke.

In February, the company's collaborating scientists isolated the molecule that responded to AF-1 and Inosine. The target was an enzyme within the central nervous system's neurons that controlled nerve growth in the brain, or in the spinal cord.

Inosine is a molecule formed by the breakdown of adenosine, a building block of genetic material and an important signaling molecule.