Kaur Charanjit, Dheen S Thameem, Ling Eng-ang
Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Acta Pharmacol Sin. 2007 Aug;28(8):1087-96. doi: 10.1111/j.1745-7254.2007.00625.x.
Amoeboid microglial cells (AMC) in the developing brain are active macrophages. The macrophagic nature of these cells has been demonstrated by many methods, such as the localization of various hydrolytic enzymes and the presence of complement type 3 surface receptors in them. More importantly is the direct visualization of these cells engaged in the phagocytosis of degenerating cells at the ultrastructural level. Further evidence of them being active macrophages is the avid internalization of tracers administered by the intravenous or intraperitoneal routes in developing rats. The potential involvement of AMC in immune functions is supported by the induced expression of major histocompatibility complex class I and II antigens on them when challenged by lipopolysaccharide or interferon-gamma. Immunosuppressive drugs, such as glucocorticoids and immune function-enhancing drugs like melatonin, affect the expression of surface receptors and antigens and the release of cytokines by AMC. Recent studies in our laboratory have shown the expression of insulin-like growth factors, endothelins, 2',3'-cyclic nucleotide 3'-phosphodiesterase, and N-methyl-D-asparate receptors. This along with the release of chemokines, such as stromal derived factor-1a and monocyte chemoattractant protein-1, suggests multiple functional roles of AMC in early brain development.
发育中的大脑中的阿米巴样小胶质细胞（AMC）是活跃的巨噬细胞。这些细胞的巨噬细胞性质已通过多种方法得到证实，例如各种水解酶的定位以及它们表面存在补体3型受体。更重要的是在超微结构水平上直接观察到这些细胞参与退化细胞的吞噬作用。它们作为活跃巨噬细胞的进一步证据是在发育中的大鼠中通过静脉或腹腔途径给予的示踪剂被大量内化。当受到脂多糖或干扰素-γ刺激时，AMC上主要组织相容性复合体I类和II类抗原的诱导表达支持了AMC在免疫功能中的潜在参与。免疫抑制药物，如糖皮质激素，以及免疫功能增强药物，如褪黑素，会影响AMC表面受体和抗原的表达以及细胞因子的释放。我们实验室最近的研究表明了胰岛素样生长因子、内皮素、2',3'-环核苷酸3'-磷酸二酯酶和N-甲基-D-天冬氨酸受体的表达。这与趋化因子如基质衍生因子-1a和单核细胞趋化蛋白-1的释放一起，表明AMC在早期大脑发育中具有多种功能作用。
