Retinoic acid does not induce formation of cilia on the surface of wound epithelial cells in axolotls

It has been reported that vitamin A palmitate induces the production of cilia on the epidermal cells of the regenerating axolotl limb, and the formation of crevices in the epidermal surface. The aim of the present investigation was to reexamine under well defined conditions the potential of retinoids to evoke the above described metaplastic changes. In order to achieve our purpose we administered axolotls with retinoic acid for 2, 4, 6, 8, and 10 days after limb amputation. The young regenerates were inspected by scanning electron microscopy (SEM). The data obtained showed that the external layer of the wound epithelium and of the stump epidermis as well was quite normal without any sign of cilia formation. In some cases, crevices were observed even in control animals.