Kinoshita T, Sasaki F
Department of Biology, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
Histochemistry. 1994 Jul;101(6):397-404. doi: 10.1007/BF00269489.
Cell proliferation was examined in the back and tail epidermis of larval Xenopus laevis using bromodeoxyuridine (BrdU). The BrdU labeling index of the back epidermis increased temporally at stage 59, followed by a rapid decrease to the same level as at stage 51. epidermis produced a new epidermal layer composed of basal cells. In vitro analysis showed that tri-iodothyronine (T3) promotes cell proliferation of basal cells but suppresses that of skein cells. Immunohistochemical studies showed that the newly formed basal cell layer functions as adult precursor cells which produce the adult epidermal cells. In contrast to the back epidermis, the labeling index of the tail epidermis decreased from stage 57. However, when the tail skin was transplanted to the back area, cell proliferation in the tail epidermis increased to the same level as that of the normal back epidermis. Cell proliferation of the back epidermis was not suppressed by transplanting the skin to the tail area. These results suggest that some promoting factors are produced in the body region and regulate the number of adult precursor cells, which determine the developmental fate of the larval skin.
使用溴脱氧尿苷（BrdU）检测了非洲爪蟾幼体背部和尾部表皮的细胞增殖情况。背部表皮的BrdU标记指数在第59阶段随时间增加，随后迅速下降至与第51阶段相同的水平。表皮产生了由基底细胞组成的新表皮层。体外分析表明，三碘甲状腺原氨酸（T3）促进基底细胞的细胞增殖，但抑制丝细胞的增殖。免疫组织化学研究表明，新形成的基底细胞层作为产生成体表皮细胞的成体前体细胞发挥作用。与背部表皮相反，尾部表皮的标记指数从第57阶段开始下降。然而，当将尾部皮肤移植到背部区域时，尾部表皮中的细胞增殖增加到与正常背部表皮相同的水平。将皮肤移植到尾部区域并不会抑制背部表皮的细胞增殖。这些结果表明，身体区域会产生一些促进因子，调节成体前体细胞的数量，而成体前体细胞决定了幼体皮肤的发育命运。
