Fig. 1

The morphological and histological appearance at different days post amputation. Gross inspection of Cynops orientalis limb regeneration (left). Samples were amputated 1 mm over the elbow at different days post-amputation. HE staining of longitudinal sections of regenerating limbs at different days post amputation (right). a Section at 3dpa. Wound stump covered by epidermis and gland cells without basement membrane. b Section at 7dpa. Undifferentiated mesenchymal cells accumulating under the thickened AEC (M: muscle, B: bone). c Section at 14dpa. Formation of blastema. d Section at 30dpa. Formation of initial limb bud. e Section of 42dpa. Regenerating limb with initial digits