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5. Wound healing and limb regeneration in amphibians: Toward perfect wound repair in mammals
Koji Tamura, Rina Ohtsuka, Aiko Kawasumi, Hitoshi Yokoyama.
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University.
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Amphibians, urodeles in particular, regenerate their limbs perfectly. In the process of limb regeneration, the skin wound initially heals as an indispensable event. Amphibian wound healing starts from the process of histolysis and dedifferentiation of mature cells underneath the wound epithelium that covers the wound site immediate after wounding. These dedifferentiated mesenchymal cells are highly proliferative under the control of nerve signals. These dedifferentiated cells are not only involved in skin regeneration but also in limb regeneration if both the nerve signals and positional information act in a stepwise manner. By contrast, the skin wound healing process in mammals results in imperfect reconstitution of injured skin with a scar when the wound penetrates to the dermis. Scar formation is a major medical problem because it results in a loss of function, movement restriction and disfigurement. Molecular and cellular mechanisms of wound healing in amphibians serve as an excellent model system toward the perfect wound repair in mammal skin. |
