Regenerating epidermis and spinal cord is essential to maintain tail regeneration in lizards. The effects of vitamin A, an inhibitor of epithelial cornification, have been studied in lizards during tail regeneration. The injection of high doses of vitamin A induces regeneration of a thinner tail with gummy consistency and suppression of the formation of a normal cartilaginous axial skeleton. Microscopic analysis reveals that all epithelia increase the secretion of glycoprotein-mucus. During the analyzed period the epidermis does not form scales and keratinocytes limit or stop the production of bundles of intermediate filament keratins and packets of corneous beta-proteins (β-keratins). Differentiation of oberhautchen and β-layers is much reduced or inhibited while α-keratinization and the formation of a corneous layer are affected as well. The effects of vitamin A are dramatic also on mesoderm cells since the treatment stimulates an invasion of blood cells likely due to the disruption of the wall of blood vessels, mesenchymal cell death (pycnosis), and diffuse phagocytosis by immune cells. A delay of cartilage differentiation and cartilage degradation due to an increase of lysosomes in these cells or released by white blood cells explains the lack of stiffness of the regenerating tail after vitamin A treatment. Regenerating muscles are variably affected, ranging from a variable necrotic effect with partial degradation of internal organelles and myofilaments to a massive or complete loss of myofibrils that do not organize in sarcomeres. In general hypervitaminosis A appears to delay epithelial but also mesodermal cell differentiation and maintains the regenerating tail in an immature condition.

中文翻译：

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尾巴再生期间在蜥蜴中服用维生素A决定了上皮的粘液生成并延迟了肌肉和软骨的分化。

表皮和脊髓的再生对于维持蜥蜴的尾巴再生至关重要。维生素A（一种上皮角质形成抑制剂）的作用已在蜥蜴的尾巴再生过程中进行了研究。注射高剂量的维生素A可以诱导细小尾巴再生，具有胶粘稠度，并抑制正常的软骨轴骨架的形成。显微镜分析显示，所有上皮细胞都增加了糖蛋白黏液的分泌。在分析期间，表皮不会形成鳞屑，角质形成细胞不会限制或停止中间丝状角蛋白束和角质β蛋白（β-角蛋白）包的产生。Oberhautchen和β层的分化大大减少或被抑制，而α-角化和角质层的形成也受到影响。维生素A对中胚层细胞的作用也很显着，因为这种疗法可能刺激血管细胞的入侵，这可能是由于血管壁破裂，间充质细胞死亡（肥大）和免疫细胞弥散性吞噬作用所致。由于这些细胞中的溶酶体增加或白细胞释放而导致的软骨分化和软骨降解延迟，说明了维生素A处理后再生尾巴缺乏刚性。再生肌肉受到不同程度的影响，范围从内部细胞器和肌丝的部分降解引起的坏死作用到肉瘤中没有组织的肌原纤维的大量或完全丧失。