A new murine model for mammalian wound repair and regeneration.

Regeneration is generally considered to be a phenomenon restricted to amphibians in which amputated limbs reform and regrow. We have recently noted a strain of mouse, the MRL, which displays a remarkable capacity for cartilagenous wound closure and provides an example of a phenomenon previously considered to be a form of regeneration. Specifically, through-and-through ear punches rapidly attain full closure with normal tissue architecture reminiscent of regeneration seen in amphibians as opposed to scarring, as usually seen in mammals. Histologically, we have demonstrated normal cell growth and microanatomy, including angiogenesis and chondrogenesis, as opposed to control C57BL/6 mice which have ear holes that contract minimally but do not close. Finally, this phenomenon is a genetically definable quantitative trait.