Bentlage C, Nikkhah G, Cunningham M G, Björklund A
Department of Physiology, Wallenberg Neuroscience Center, Sölvegatan 17, Lund, S-223 62, Sweden.
Exp Neurol. 1999 Sep;159(1):177-90. doi: 10.1006/exnr.1999.7110.
The aim of this study was to determine whether the growth of axons along the nigrostriatal pathway from fetal dopamine cells, transplanted into the substantia nigra of young postnatal 6-OHDA-lesioned rats, is dependent on the age of the host brain. Neonatal rats were lesioned bilaterally by intraventricular injection of 6-OHDA at postnatal day 1 (P1) and received grafts of E14 ventral mesencephalon at day 3 (group P3), day 10 (group P10), or day 20 (group P20) into the right substantia nigra. One lesioned group was left untransplanted. Six months after surgery the animals were subjected to analysis of drug-induced rotation following injection of amphetamine, apomorphine, a D1 agonist (SKF38393), or a D2 agonist (Quinpirole). Animals transplanted intranigrally at day 3 and day 10 showed a strong amphetamine-induced rotational bias toward the side contralateral to the transplant. Animals transplanted into substantia nigra at P20, like the lesioned control animals, showed no rotational bias. Apomorphine and selective D1 and D2 agonists induced ipsilateral turning behavior in the P3 and P10 group, but not in the P20 or the lesion control groups. Immunofluorescence histochemistry in combination with retrograde axonal tracing, using FluoroGold injection into the ipsilateral caudate-putamen showed colocalization of tyrosine hydroxylase and FluoroGold in large numbers of transplanted neurons in the animals transplanted at postnatal day 3 and postnatal day 10, which was not observed in the group P20. The lesion control group showed a 90% complete lesion of the TH-positive cells in the substantia nigra while largely sparing the neurons in the ventral tegmental area. The results indicate that intranigral grafts can be placed accurately and survive well within the substantia nigra region at various time points during postnatal development. Furthermore, embryonic dopamine neurons have the ability to extend axons along the nigrostriatal pathway and reconnect with the dopamine-depleted striatum when transplanted at postnatal day 3 and postnatal day 10, but not at postnatal day 20.
本研究的目的是确定移植到出生后6 - 羟基多巴胺（6-OHDA）损伤的幼鼠黑质中的胎儿多巴胺细胞沿黑质纹状体通路的轴突生长是否依赖于宿主脑的年龄。新生大鼠在出生后第1天（P1）通过脑室内注射6-OHDA进行双侧损伤，并在第3天（P3组）、第10天（P10组）或第20天（P20组）将胚胎第14天（E14）的腹侧中脑移植到右侧黑质。一个损伤组未进行移植。术后6个月，给动物注射苯丙胺、阿扑吗啡、D1激动剂（SKF38393）或D2激动剂（喹吡罗）后，对药物诱导的旋转进行分析。在第3天和第10天进行黑质内移植的动物表现出强烈的苯丙胺诱导的向移植对侧的旋转偏向。在P20时移植到黑质的动物，与损伤对照组动物一样，未表现出旋转偏向。阿扑吗啡以及选择性D1和D2激动剂在P3和P10组诱导了同侧转向行为，但在P20组或损伤对照组中未诱导出该行为。通过将荧光金注射到同侧尾状核 - 壳核，结合逆行轴突追踪进行免疫荧光组织化学分析，结果显示在出生后第3天和第10天移植的动物中，大量移植神经元中酪氨酸羟化酶和荧光金共定位，而在P20组中未观察到这种情况。损伤对照组黑质中TH阳性细胞有90%完全损伤，而腹侧被盖区的神经元大部分未受影响。结果表明，在出生后发育的不同时间点，黑质内移植可以准确放置且在黑质区域内存活良好。此外，胚胎多巴胺神经元在出生后第3天和第10天移植时，有能力沿黑质纹状体通路延伸轴突并与多巴胺耗竭的纹状体重新连接，但在出生后第20天移植时则不能。
