MORPHOLOGICAL AND BIOCHEMICAL STUDY IN BRAIN TRANSPLANTATION OF NEURAL TISSUE

从细胞系中建立的神经细胞可以为移植到大脑的细胞提供一个很好的特征来源，这是胎儿神经元的替代品。用含有ras癌基因的逆转录病毒感染pc12细胞系，可使其在不需要神经生长因子（NGF）的情况下向神经元分化。我们发现，移植到正常成年大鼠纹状体上的肿瘤性、未成熟的PC12细胞会导致大的出血性空洞的短暂形成，并且不能存活。PC12细胞经Kirsten-ras小鼠肉瘤病毒感染分化后，移植到同脑的相反纹状体，存活至少8周，并产生神经突。免疫组织化学检测，这些神经元样细胞及其神经突保留酪氨酸羟化酶和胆碱乙酰转移酶。因此，ras引发的PC12细胞可以作为体内胆碱能和多巴胺能递质的连续来源，而不需要外源性NGF。除了pc12细胞系外，我们还发现大鼠羊膜上皮细胞可以分化为神经元细胞，因此这些细胞也可能作为非肿瘤候选细胞用于神经元移植。

Neuronal cells establishing from cell lines can offer a well-characterized source of cells for transplantation to the brain that is an alternative to fetal neurons. The infection of the PC 12 cell line with a retrovirus containing ras-oncogene leads to their neuronal differentiation without the need of nerve growth factor (NGF). We find that neoplastic, naive PC12 cells grafted to the striatum of normal adult rats cause the transient formation of large hemorrhagic cavities and do not survive. After differentiation by infection with Kirsten-ras murine sarcoma virus, and transplantation to the opposite striatum of the same brain, PC12 cells survive for at least 8 weeks and emit neurites. These neuron-like cells and their neurites retain tyrosine hydroxylase and choline acetyl transferase, as detected immunohistochemically. Thus, ras-primed PC12 cells may serve as a continuous source for both cholinergic and dopaminergic transmitters, in vivo, without the need of exogenous NGF.In addition to the PC 12 cell lines, we also find that rat amniotic epithelial cells can be differentiated to neuronal cells, thus these cells also may be useful for neuronal transplantation as a non-neoplastic candidate.