老年大鼠蓝斑胶质细胞超微结构的变化

Ultrastructure Changes of Glial Cells in Locus Ceruleus of Old Rat

本实验以青年鼠为对照,观察老年大鼠蓝班内胶质细胞超微结构的改变.结果显示:老年大鼠蓝斑内出现许多肥大星形胶质细胞,这些细胞胞浆内含有丰富的核糖体、粗面内质网和线粒体.少突胶质细胞增生,胞浆含有大量细胞器、突起内含有变性的轴突、终末和树突.小胶质细胞也增生,其胞浆内出现大量脂滴、脂褐素.在一些较大的腔隙内,可观察到巨噬细胞.与此同时,退变的星形胶质细胞亦可见到,这些细胞浆内出现大量致密体、变性的线粒体、胶质原纤维和糖元颗粒.上述结果提示:在脑衰老过程中,胶质细胞的形态和数量已发生了一系列变化,这些变化一方面有利于修复变性的神经元和清除坏死的神经元,另一方面也提示星形胶质细胞本身面临着退变和死亡.

Compared with the young rat, the ultrastructure changes of glial cells in locus ceruleus (LC) of old rat were observed under EM. The results were showed as follow?There appear many reactive astrocytes which cytoplasm are filled with a lot of ribosomes and rough endo-plasmic reticulums and mitochondria. Oligodendrocytes increase in number. These cells which processes contain degenerative axons and terminals and dendrites are rich with or-ganelles. Microglial cells which show the intracytopiasmic accumulation of fat droplets and lipofuscins also increase in number. Besides, the macrophages are found within the large space in LC. Meanwhile, degenerative astrocytes are also found, which are accompanied with many eletrondense bodies, degenerating mitochodrias, intermediate filaments and glucogen accumulation in the cytoplasm. these results suggest that in brain aging process, glial cells undergo a serial changes in morphology and in number, which may be helpful to repare degenerative neurons and clear dead neurons on one hand, and show that astrocytes themselfies may face degeneration and death on the other hand.