Wu C H, Wang H J, Wen C Y, Lien K C, Ling E A
Department of Anatomy, Taipei Medical College, Taiwan, ROC.
Neurosci Res. 1997 Feb;27(2):133-41. doi: 10.1016/s0168-0102(96)01140-6.
The present study describes the response of amoeboid and ramified microglial cells in the corpus callosum to intraperitoneal lipopolysaccharide injections in postnatal rats as examined by lectin histochemical staining and electron microscopy. In 1 day old rats receiving endotoxin injections and sacrificed at various time intervals, the lectin labelling of amoeboid/ramified microglia was greatly enhanced. The increased labelling persisted in some ramified microglia in rats killed at 14 and 21 days of age; otherwise in normal or control animals of the corresponding stages, the same cells were very weakly stained. In rats killed at 2 days of age after intraperitoneal lipopolysaccharide injection, the number of microglia appeared to increase, but this was reduced at 7 days of age. The lectin-labelled amoeboid/ramified microglia were frequently seen adherent to the outer walls of the callosal blood vessels where infiltrated lymphocytes were also observed. Ultrastructurally, some lectin-labelled microglial cells underwent degeneration and were engulfed by other lectin-positive cells. After endotoxin injections, microglial cells, notably the amoeboid form, showed extensive ruffling at their cell membrane, massive accumulation of lysosomes and increased staining of lectin at their Golgi apparatus. A similar lectin labelling pattern was also observed in ramified microglia of lipopolysaccharide-injected rats. It is concluded that both amoeboid and ramified microglial cells in postnatal rats responded to endotoxin injections as reflected by their enhanced lectin labelling at the surface membrane, lysosomes and Golgi apparatus. It is suggested that such changes may be involved in synthesis and/or modification of galactosyl glycoconjugates probably for the increased production of membranous glycoproteins or lysosomal enzymes.
本研究描述了通过凝集素组织化学染色和电子显微镜检查，出生后大鼠胼胝体中阿米巴样和分支状小胶质细胞对腹腔注射脂多糖的反应。在接受内毒素注射并在不同时间间隔处死的1日龄大鼠中，阿米巴样/分支状小胶质细胞的凝集素标记大大增强。在14日龄和21日龄处死的大鼠中，一些分支状小胶质细胞中增加的标记持续存在；否则，在相应阶段的正常或对照动物中，相同的细胞染色非常弱。在腹腔注射脂多糖后2日龄处死的大鼠中，小胶质细胞数量似乎增加，但在7日龄时减少。经常可以看到凝集素标记的阿米巴样/分支状小胶质细胞附着在胼胝体血管的外壁上，在那里也观察到浸润的淋巴细胞。超微结构上，一些凝集素标记的小胶质细胞发生变性并被其他凝集素阳性细胞吞噬。内毒素注射后，小胶质细胞，尤其是阿米巴样形态，在其细胞膜处显示出广泛的褶皱，溶酶体大量积累，高尔基体处凝集素染色增加。在注射脂多糖的大鼠的分支状小胶质细胞中也观察到类似的凝集素标记模式。结论是，出生后大鼠的阿米巴样和分支状小胶质细胞对内毒素注射均有反应，表现为其表面膜、溶酶体和高尔基体处凝集素标记增强。提示这些变化可能参与半乳糖基糖缀合物的合成和/或修饰，可能是为了增加膜糖蛋白或溶酶体酶的产生。
