Kozlowski D A, Connor B, Tillerson J L, Schallert T, Bohn M C
Department of Pediatrics, Children's Memorial Institute for Education and Research, Chicago, Illinois 60614, USA.
Exp Neurol. 2000 Nov;166(1):1-15. doi: 10.1006/exnr.2000.7463.
The effects of delivering GDNF via an adenoviral vector (AdGDNF) 1 week after lesioning dopaminergic neurons in the rat substantia nigra (SN) with 6-hydroxydopamine (6-OHDA) were examined. Rats were unilaterally lesioned by injection of 6-OHDA into the striatum, resulting in progressive degeneration of dopaminergic neurons in the SN. One week later, when substantial damage had already occurred, AdGDNF or a control vector harboring beta-galactosidase (AdLacZ) was injected into either the striatum or SN (3.2 x 10(7) PFU/microl in 2 microl). Rats were examined behaviorally with the amphetamine-induced rotation test and for forelimb use for weight-bearing movements. On day 30 postlesion, the extent of nigrostriatal tract degeneration was determined by injecting a retrograde tracer (FluoroGold) bilaterally into the lesioned striatum. Five days later, rats were sacrificed within 2 h of amphetamine injection to examine amphetamine-induced Fos expression in the striatum, a measure of dopaminergic-dependent function in target neurons. AdGDNF injection in the SN rescued dopaminergic neurons in the SN and increased the number of dopaminergic neurons that maintained a connection to the striatum, compared to rats injected with AdLacZ. Further support that these spared SN cells maintained functional connections to the striatum was evidenced by increased Fos expression in striatal target neurons and a decrease in amphetamine-induced rotation. In contrast to the effects observed in rats injected with AdGDNF in the SN, rats injected with AdGDNF in the striatum did not exhibit significant ameliorative effects. This study demonstrates that experimentally increasing levels of GDNF biosynthesis near the dopaminergic neuronal soma is effective in protecting the survival of these neurons and their function even when therapy is begun after 6-OHDA-induced degeneration has commenced. Thus, GDNF gene therapy may ameliorate the consequences of Parkinson's disease through rescuing compromised dopaminergic neurons.
研究了在大鼠黑质（SN）中用6-羟基多巴胺（6-OHDA）损伤多巴胺能神经元1周后，通过腺病毒载体（AdGDNF）递送胶质细胞源性神经营养因子（GDNF）的效果。通过向纹状体注射6-OHDA对大鼠进行单侧损伤，导致SN中多巴胺能神经元的渐进性退化。1周后，当已经发生实质性损伤时，将AdGDNF或携带β-半乳糖苷酶的对照载体（AdLacZ）注射到纹状体或SN中（2微升中含3.2×10⁷ 个噬斑形成单位/微升）。通过苯丙胺诱导的旋转试验对大鼠进行行为检查，并检查前肢在负重运动中的使用情况。在损伤后第30天，通过双侧向损伤的纹状体注射逆行示踪剂（氟金）来确定黑质纹状体束的退化程度。五天后，在注射苯丙胺后2小时内处死大鼠，以检查苯丙胺诱导的纹状体中Fos表达，这是靶神经元中多巴胺能依赖性功能的一项指标。与注射AdLacZ的大鼠相比，在SN中注射AdGDNF可挽救SN中的多巴胺能神经元，并增加与纹状体保持连接的多巴胺能神经元数量。纹状体靶神经元中Fos表达增加以及苯丙胺诱导的旋转减少证明了这些保留的SN细胞与纹状体保持功能连接。与在SN中注射AdGDNF的大鼠所观察到的效果相反，在纹状体中注射AdGDNF的大鼠未表现出明显的改善作用。这项研究表明，即使在6-OHDA诱导的退化开始后才开始治疗，实验性地提高多巴胺能神经元胞体附近GDNF的生物合成水平对于保护这些神经元的存活及其功能也是有效的。因此，GDNF基因治疗可能通过挽救受损的多巴胺能神经元来改善帕金森病的后果。
