IL-10 in healing of nerves

Sheffield, UK -

There seems to be some connections between the immune system and various stem cell niches. For example, while the role of the stromal cells is to provide nutrients for the bone marrow hematopoietic stem cells, these cells also play anti-inflammatory functions. In some situations activations of enzymes associated with inflammation, such as the p38 MAPK are known to inhibit regeneration either fetally, or in adults.

In a recent paper (Atkins et al. Interleukin-10 reduces scarring and enhances regeneration at a site of sciatic nerve repair. J Peripher Nerv Syst. 2007 Dec;12(4):269-76) investigators assessed the effects of the antiinflammatory cytokine IL-10 on healing and sciatic nerve regeneration.

B6 mice had the left sciatic nerve severed and rapidly re-attached by four epineurial sutures. Epineurial means literally "situated upon a neural arch".

TGF-beta 3, IL-10 or saline was injected before and after the injury proximal to the area of tissue damage.

At the timepoint of one and a half months after injury functional improvement was quantified by compound action potential analyis, as well as evaluation of collagen deposition and myelination of axons surrounding the injury.

IL-10 treatment preserved the compound action potential and maintained collagen levels, whereas control TGF-beta 3 and saline treated groups had significantly lower compound action potentials and much higher levels of collagen deposition.

None of the treatments were able to induce remyelination.

These data suggest that the antiinflammatory activities of IL-10 may also have some ability to inhibit the generation of scar tissue. Interestingly TGF-beta has previously been shown to inhibit stem cell proliferation so the next experiment should be assessment of anti-TGF-beta antibody together with administration of IL-10.