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Thursday, October 7th, 2010

Spinal Cord Tissue Regenerated with Sodium

by wendy

By Ben Coxworth

15:35 October 5, 2010

In a study that could have implications for the treatment of traumatic injuries in humans, scientists at Tufts University in Massachusetts have succeeded in getting tadpoles to regrow amputated tails. The researchers first noted that when the tails were cut off of young Xenopus laevis (African clawed frog) tadpoles, a localized increase in sodium ions occurred at the amputation site, which allowed the tail to regenerate – something which tadpoles lose the ability to do as they mature. However, after an hour of treatment with a drug cocktail that triggered an influx of sodium ions into injured cells, older tadpoles were also able to regenerate their tails. Given that tadpole tails contain spinal cord, muscle, nerves and other materials, it’s possible that the process might someday be able to regenerate the spinal cords, or even limbs, of people.

An unregenerated tail on an untreated tadpole (top), and a regenerated tail on one that received the treatment (bottom) (Photos: Ai-Sun Tseng and Michael Levin-Tufts University)

The Tufts scientists stated that their approach breaks new ground, in that it doesn’t require gene therapy, it’s bioelectric as opposed to chemically-based, and can still work even after an injury has healed over. In their tests, tail regeneration could still be induced up to 18 hours after amputation.

“We have significantly extended the effective treatment window, demonstrating that even after scar-like wound covering begins to form, control of physiological signals can still induce regeneration,” said Tufts Professor of Biology Michael Levin. “Artificially causing an influx of sodium for just one hour can overcome a variety of problems, such as the decline in regenerative ability that comes with age and the effect of regeneration-blocking drugs.”

The use of tadpole tails in the study is significant, in that they regenerate themselves the same way that human tissue does – each cell makes more of itself. By contrast, certain other animals regenerate body parts through transdifferentiation, in which one cell type turns into another, or through adult stem cell differentiation.

The research was published in the Journal of Neuroscience.

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