Okoye G S, Powell E M, Geller H M
Department of Surgery, UMDNJ-Robert Wood Johnson Medical School, Piscataway 08854, USA.
J Comp Neurol. 1995 Nov 27;362(4):524-34. doi: 10.1002/cne.903620407.
The A7 cell line is an SV40 large T antigen-immortalized astrocyte cell line produced from the neonatal rat optic nerve. Previous studies have demonstrated that A7 cells provide a favorable environment for the survival and growth of cultured neurons and can also stimulate axonal growth after grafting into the rat striatum. The current study was designed to investigate whether A7 cells grafted into adult rat striatum can migrate away from the implantation site. A7 cells were labelled in culture by incorporation of bromodeoxyuridine (BrdU) or by expression of an alkaline phosphatase transgene. The labelled cells were then transplanted into the left striatum of normal adult rats by introducing a blunt-end 22 gauge needle through a trephine hole. The rats were euthanized at periods of up to 30 days after grafting. The A7 cells did not appear to alter the cytoarchitecture of the surrounding brain parenchyma. Labelled A7 cells were observed in both gray and white matter areas, and many were located in areas free of damage due to the implantation procedure. The migration of the BrdU-labelled A7 cells with respect to the implantation needle track was determined on coronal sections. The radial migration distance from the needle tract was similarly determined on horizontal sections. A7 cells migrated progressively longer distances with increasing survival time of the animals: The largest migration distance (1,125 +/- 52 microns) occurred at 30 days after grafting with an estimated migration rate of 31 microns per day. There was no significant directional polarity in the migration of these cells within the striatum. Some of the labelled A7 nuclear profiles were associated with blood vessels, some appeared to be associated with fiber bundles within the striatum, and some were found within the gray matter without apparent association with any anatomical structure. These results demonstrate that A7 immortalized astrocytic cells migrate away from a single implantation site following grafting into the adult rat striatum to populate a large area of the striatum.
A7细胞系是一种由新生大鼠视神经产生的、经猿猴病毒40（SV40）大T抗原永生化的星形胶质细胞系。先前的研究表明，A7细胞为培养的神经元的存活和生长提供了有利环境，并且在移植到大鼠纹状体后还能刺激轴突生长。当前的研究旨在调查移植到成年大鼠纹状体中的A7细胞是否能够从植入部位迁移离开。通过掺入溴脱氧尿苷（BrdU）或通过碱性磷酸酶转基因的表达在培养物中标记A7细胞。然后通过将一根钝头22号针穿过一个环钻孔，将标记的细胞移植到正常成年大鼠的左侧纹状体中。在移植后长达30天的时间段内对大鼠实施安乐死。A7细胞似乎并未改变周围脑实质的细胞结构。在灰质和白质区域均观察到了标记的A7细胞，并且许多细胞位于因植入操作而未受损伤的区域。在冠状切片上确定BrdU标记的A7细胞相对于植入针轨迹的迁移情况。在水平切片上同样确定从针道的径向迁移距离。随着动物存活时间的增加，A7细胞迁移的距离逐渐变长：最大迁移距离（1125±52微米）出现在移植后30天，估计迁移速率为每天31微米。这些细胞在纹状体内的迁移没有明显的方向极性。一些标记的A7细胞核轮廓与血管相关，一些似乎与纹状体内的纤维束相关，还有一些在灰质内被发现，且与任何解剖结构均无明显关联。这些结果表明，A7永生化星形胶质细胞在移植到成年大鼠纹状体后会从单个植入部位迁移离开，从而占据纹状体的大片区域。
