Tissue Eng
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Comparative Study
A new strategy to produce sustained growth of central nervous system axons: continuous mechanical tension.
Although a primary strategy to repair spinal cord and other nerve injuries is to bridge the damage with axons, producing axons of sufficient length and number has posed a significant challenge. Here, we explored the ability of integrated central nervous system (CNS) axons to grow long distances in response to continuous mechanical tension. Neurons were plated on adjacent membranes and allowed to integrate, including the growth of axons across a 50-microm border between the two membranes. ⋯ This is the first evidence that the center portion of synapsed CNS axons can exhibit sustained "stretch-induced growth." This may represent an important growth mechanism for the elongation of established white matter tracts during development. We also found by doubling the stretch rate to 7 microm/5 min that the axon bundles could not maintain growth and disconnected in the center of the gap by 3 days of stretch, demonstrating a tolerance limit for the rate of axonal growth. We propose that this newfound stretch-induced growth ability of integrated CNS axons may be exploited to produce transplant materials to bridge extensive nerve damage.