NT-3 And Axon Bridging After Injury

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NT-3 And Axon Bridging After Injury

http://www.medicalnewstoday.com/medicalnews.php?newsid=52330

, Leonard , Mark H. Tuszynski, and Armin Blesch

Neurotrophic factors can stimulate the growth of axons after spinal

cord injury. For example, when genetically modified cells expressing

the neurotrophin NT-3 are grafted into the site of injury, axons grow

into the lesion. However, these axons rarely exit the graft to

innervate the adjoining spinal cord.

This week, et al. tried to overcome this stumbling block to

regeneration. They transplanted grafts of syngeneic marrow stromal

cells overexpressing NT-3 into dorsal column lesions in the adult rat

spinal cord; this fiber tract carries ascending sensory axons. The

authors then injected lentiviral vectors expressing NT-3 at sites

rostral to the graft, thus establishing an extended gradient of

neurotrophic factor to guide axons growth.

In injected animals, axons indeed bridged the gap and extended beyond

the graft boundary but did not proceed further than 500 µm, although

NT-3 gradients extended further. Thus, the growth pattern was not

strictly " chemotropic. "