Scar-Free Wound Healing Following Full-Thickness Cutaneous Wounding in the Tail and Body of Scincella tsinlingensis.

The cutaneous wounds of trunk and tail healing scar-free or with scar were different in lizard species. Fullthickness cutaneous injuries of tail and body of Scincella tsinlingensis were examined by histomorphological and immunohistochemistrical methods. The results showed that all injuries healed without scarring. The process of the wound healing of S. tsinlingensis involved hemostasis, re-epithelialization, proliferation and remodelling, which also could be further subdivided into six stages. Stage I, 0-2 day post wound (dpw), the blood oozed gradually, no obvious wound contraction, minimal blood loss. Stage II, 2-10 dpw, the wound bed covered by the fibrin clot of blood, tissue fluid and tissue debris. Stage III, 7d-15 dpw, the wrinkled wound epitheliums was gradually stratified, and its surface was keratinized and exfoliated. Stage IV, 10-28 dpw, pigment cells were distributed at the boundary between epidermis and dermis, with few blood vessels and no granulation tissue formation. Stage V, 20-70 dpw, opaque scales covered the wound epithelium with randomly scattered melanophores in the base of the epidermis. Stage VI, 45-135 dpw, the epidermis and dermis restored to the thickness of the original skin. Regenerated scales were similar to scales of the uninjured dermis. The positive immunostaining of matrix metalloproteinases-9, cytokeratin 6, alpha smooth muscle actin, caspase 3 and transforming growth factor-b3 showed the specificity of healing period and different stages, which participated in skin wounds healing of S. tsinlingensis. [ABSTRACT FROM AUTHOR]