Yokoyama Akiko, Sakamoto Aiko, Kameda Kenji, Imai Yoshinori, Tanaka Junya
Department of Molecular and Cellular Physiology, School of Medicine, Ehime University, Toon, Ehime 791-0295, Japan.
Glia. 2006 May;53(7):754-68. doi: 10.1002/glia.20332.
Rat primary microglia (MG) acquired a multipotent property to give rise to neuroectodermal cells through two-step culture in 10 and 70% serum-supplemented media for 5 days. Such multipotent MG, called promicroglioblasts (ProMGBs), formed cell aggregates, which generated cells with neuroectodermal phenotypes shortly after their transfer into serum-free medium. As revealed by immunohistochemistry, there were a few MG expressing NG2 chondroitin sulfate proteoglycan (NG2) in the neonatal rat brain. Primary culture from the neonatal brain contained NG2+ MG, which appeared to be the source of NG2+ ProMGB aggregates. The aggregates were MG marker+/NG2+/GFAP+/NCAM+/S-100beta- and had alkaline phosphatase activity. The marked accumulation of NG2+ MG was observed close to stab wounds made in the mature rat brain. The accumulated NG2+ MG in the wound gradually decreased in number, but the cells persisted up to 150 days postlesioning. In addition, GFAP immunoreactivity increased markedly around the wound. The NG2+ MG in the wounds separated with trypsin-EDTA formed NG2+ aggregates in 70% serum-supplemented medium and then transformed into cells with neuroectodermal phenotypes in serum-free medium. Although it is difficult to separate viable neurons from mature brains, cells from stab wounds generated process-bearing beta-tubulin III+ cells in vitro easily. These data suggest that NG2+ MG in normal developing or pathologic brains are involved in the genesis or regeneration of the brain.
大鼠原代小胶质细胞（MG）通过在含10%和70%血清的培养基中进行两步培养5天，获得了产生神经外胚层细胞的多能特性。这种多能MG，称为前小胶质母细胞（ProMGBs），形成细胞聚集体，在转移到无血清培养基后不久，这些聚集体产生具有神经外胚层表型的细胞。免疫组织化学显示，新生大鼠脑中存在少数表达硫酸软骨素蛋白聚糖NG2的MG。新生脑的原代培养物中含有NG2+ MG，它们似乎是NG2+ ProMGB聚集体的来源。这些聚集体为MG标记物阳性/NG2阳性/胶质纤维酸性蛋白（GFAP）阳性/神经细胞黏附分子（NCAM）阳性/S-100β阴性，并具有碱性磷酸酶活性。在成年大鼠脑刺伤处附近观察到NG2+ MG明显聚集。伤口处聚集的NG2+ MG数量逐渐减少，但这些细胞在损伤后150天仍持续存在。此外，伤口周围GFAP免疫反应性明显增强。用胰蛋白酶-乙二胺四乙酸（EDTA）分离的伤口处的NG2+ MG在含70%血清的培养基中形成NG2+聚集体，然后在无血清培养基中转化为具有神经外胚层表型的细胞。虽然从成年脑中分离活神经元很困难，但刺伤处的细胞在体外很容易产生带有突起的β-微管蛋白III阳性细胞。这些数据表明，正常发育或病理状态下脑中的NG2+ MG参与了脑的发生或再生。
