Rabié A, Favre C, Clavel M C, Legrand J
Brain Res. 1979 Feb 9;161(3):469-79. doi: 10.1016/0006-8993(79)90676-0.
Young rats made hypothyroid by propylthiouracil (PTU) received a daily physiological dose of thyroxine (T4) from day 0, 4, 6, 8, 10, 11, 12 or 13 and their cerebella were studied on day 14. With the very low doses of T4 used and when the treatment was started at birth, cerebellar development was nearly normal in terms of the parameters studied (cell formation, migration, maturation and death). The effect of T4 on cell formation appeared after two days. With the same latency, T4 induced migration of the newly-formed granule cells. The effects on those processes requiring cell movements over long distances, e.g. the number of cells in the internal granular layer or the thickness of the molecular layer, were longer to appear. The most rapidly affected parameter was the pyknotic index in the internal granular layer. This index was half. The increased cell death in the cerebellum of hypothyroid rats is probably related to the decreased synaptogenetic competence of Purkinje cells. The rapidity of the effect of T4 on the pyknotic index may be related to an important effect of this hormone on the formation of synapses and, more generally, on the mechanisms of neuronal maturation.
用丙硫氧嘧啶（PTU）使幼鼠甲状腺功能减退，从第0、4、6、8、10、11、12或13天开始每天给予生理剂量的甲状腺素（T4），并在第14天对其小脑进行研究。使用的T4剂量非常低，且在出生时开始治疗，就所研究的参数（细胞形成、迁移、成熟和死亡）而言，小脑发育几乎正常。T4对细胞形成的影响在两天后出现。具有相同的潜伏期，T4诱导新形成的颗粒细胞迁移。对那些需要细胞远距离移动的过程的影响，例如内颗粒层中的细胞数量或分子层的厚度，出现得较晚。受影响最快的参数是内颗粒层中的固缩指数。该指数减半。甲状腺功能减退大鼠小脑中细胞死亡增加可能与浦肯野细胞突触形成能力下降有关。T4对固缩指数的快速影响可能与该激素对突触形成以及更普遍地对神经元成熟机制的重要作用有关。
