ELECTRON-MICROSCOPIC AUTORADIOGRAPHIC STUDIES OF GLIOGENESIS IN RAT OPTIC-NERVE .2. TIME OF ORIGIN
ELECTRON-MICROSCOPIC AUTORADIOGRAPHIC STUDIES OF GLIOGENESIS IN RAT OPTIC-NERVE .2. TIME OF ORIGIN
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DOI：
10.1002/cne.901690304
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发表时间：
1976-01-01
影响因子：
2.5
通讯作者：
STOCKS, A
中科院分区：
文献类型：
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作者：
SKOFF, RP;PRICE, DL;STOCKS, A
用类似于神经元起源时间测定的~ 3 H-胸腺嘧啶核苷放射自显影技术研究了大鼠视神经星形胶质细胞和少突胶质细胞的起源时间。星形胶质细胞形成于胚胎晚期和出生后的整个发育过程中，而少突胶质细胞仅在出生后产生。少数星形胶质细胞早在妊娠15.5天就进行了最后的细胞分裂，但大多数星形胶质细胞直到出生后发育的第1周才产生。虽然超过一半的星形胶质细胞的最后细胞分裂发生在出生后第1周结束之前，完全成熟的纤维星形胶质细胞，直到14天的年龄后，在电子显微镜下观察。这种时间滞后意味着这些早期产生的细胞的分化在2-3周的间隔内逐渐发生。少突胶质细胞开始它们的最后分裂在髓鞘形成开始前1天或2天（出生后6-7天），但绝大多数是在髓鞘形成期间产生的。在几乎所有的轴突都有髓鞘形成后，少突胶质细胞仍在少量生成。这些晚期形成的细胞通常在外观上比早期形成的细胞分化程度低;少突胶质细胞的分化程度可能取决于可用于髓鞘形成的轴突的数量。与星形胶质细胞一样，少突胶质细胞从最终细胞分裂到转化为形态分化细胞的时间约为2周。在视神经的横切面上，高度标记的神经胶质细胞随机分布，表明单个细胞类型没有时间-径向梯度。控制胶质细胞生成的因素与控制神经元生成的因素明显不同。
The time of origin for astrocytes and oligodendrocytes in rat optic nerve was studied by 3H-thymidine autoradiographic techniques similar to those used in dating the time of origin for neurons. Astrocytes were formed throughout late embryonic and all of postnatal development, while oligodendrocytes were generated only during the postnatal period. A few astroglia underwent their final cell division as early as 15.5 days of gestation, but most astrocytes were not generated until the 1st wk of postnatal development. Although the final cell division for more than half of the astrocytes took place before the end of the 1st postnatal week, fully mature, fibrous astrocytes were not observed in electron micrographs until after 14 days of age. This time lags implies that the differentiation of these early generated cells takes place gradually over a 2-3 wk interval. Oligodendroglia begin their final division a day or 2 before the onset of myelination (6-7 days postnatal), but the vast majority were produced during the period of myelinogenesis. After almost all of the axons were myelinated, oligodendrocytes were still being generated in small numbers. These late forming cells were generally less differentiated in appearance than those formed earlier; the degree of differentiation of oligodendrocytes may be dependent upon the number of axons available for myelination. As with astrocytes, oligodendrocytes showed a lag of about 2 wk from the time of final cell division until they transform into morphologically differentiated cells. In transverse sections of the optic nerve heavily labeled neuroglia were randomly distributed, indicating there were no temporal-radial gradients for the individual cell types. The factors controlling gliogenesis are apparently different from those governing neuronogenesis.