Apostolides C, Sanford E, Hong M, Mendez I
Department of Surgery (Division of Neurosurgery), Dalhousie University, Halifax, Nova Scotia, Canada.
Neuroscience. 1998 Mar;83(2):363-72. doi: 10.1016/s0306-4522(97)00369-2.
Glial cell line-derived neurotrophic factor, the newest member of the transforming growth factor-beta superfamily, has been shown to promote the survival and differentiation of dopaminergic neurons in the ventral mesencephalon. Glial cell line-derived neurotrophic factor has been implicated in both the in vitro and in vivo recovery of mesencephalic dopaminergic cells challenged with the neurotoxins 1-methyl-4-phenylpyridinium and 6-hydroxydopamine. Previous studies have shown increased survival of intrastriatally transplanted dopaminergic cells when followed by infusion of neurotrophic factors such as basic fibroblast growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor. However, the effects of glial cell line-derived neurotrophic factor co-administered with dopaminergic cells prior to implantation in the host striatum have not been studied. In the present study, the hypothesis was that treating fetal ventral mesencephalic tissue containing the dopaminergic substantia nigra with glial cell line-derived neurotrophic factor either during storage or at the time of transplantation, would enhance grafted dopaminergic cell survival and functional reinnervation of the host striatum in the unilaterally 6-hydroxydopamine-lesioned rat. To test this hypothesis, two experiments were performed. In the first experimental group (n = 7), fetal ventral mesencephalons from embryonic day 14 rats were maintained in hibernation medium containing glial cell line-derived neurotrophic factor (1 migrogram/ml) at 4 degrees C for six days prior to dissociation and stereotactic implantation into the host striatum: the control group (n = 5) received tissue hibernated without glial cell line-derived neurotrophic factor. The second experimental group (n = 8) received fresh fetal ventral mesencephalic tissue treated with glial cell line-derived neurotrophic factor (0.2 microgram/microliter) while the control group (n = 5) received the fresh graft with no glial cell line-derived neurotrophic factor. Transplantation success was assessed by behavioural analysis (rotometry) and tyrosine hydroxylase immunohistochemistry. Cell counts of tyrosine hydoxylase-stained sections revealed a statistically significant increase in tyrosine hydroxylase-positive neurons in grafts exposed to glial cell line-derived neurotrophic factor during hibernation as compared to control grafts. In addition, there was a statistically significant enhancement of fibre density in the glial cell line-derived neurotrophic factor hibernation graft group as compared to the glial cell line-derived neurotrophic factor fresh graft group. Behavioural analysis three weeks post-grafting exhibited a statistically significant decrease in amphetamine-induced rotations in animals transplanted with glial cell line-derived neurotrophic factor grafts as compared to control grafts. These findings suggest that storing dopaminergic cells in a glial cell line-derived neurotrophic factor-containing medium prior to transplantation increases graft survival, graft derived fibre outgrowth, and behavioural recovery in the adult host. This observation has potential implications for enhancing the efficacy of neural transplantation in the treatment of Parkinson's disease.
胶质细胞系源性神经营养因子是转化生长因子-β超家族的最新成员，已被证明可促进中脑腹侧多巴胺能神经元的存活和分化。胶质细胞系源性神经营养因子与用神经毒素1-甲基-4-苯基吡啶鎓和6-羟基多巴胺攻击的中脑多巴胺能细胞的体外和体内恢复均有关。先前的研究表明，纹状体内移植的多巴胺能细胞在输注诸如碱性成纤维细胞生长因子、脑源性神经营养因子和胶质细胞系源性神经营养因子等神经营养因子后存活率增加。然而，在植入宿主纹状体之前将胶质细胞系源性神经营养因子与多巴胺能细胞共同给药的效果尚未得到研究。在本研究中，假设是在储存期间或移植时用胶质细胞系源性神经营养因子处理含有多巴胺能黑质的胎儿腹侧中脑组织，将提高在单侧6-羟基多巴胺损伤的大鼠中移植的多巴胺能细胞的存活率以及宿主纹状体的功能性再支配。为了验证这一假设，进行了两项实验。在第一个实验组（n = 7）中，来自胚胎第14天大鼠的胎儿腹侧中脑在解离并立体定向植入宿主纹状体之前，于4℃在含有胶质细胞系源性神经营养因子（1微克/毫升）的冬眠培养基中维持6天：对照组（n = 5）接受未添加胶质细胞系源性神经营养因子而冬眠的组织。第二个实验组（n = 8）接受用胶质细胞系源性神经营养因子（0.2微克/微升）处理的新鲜胎儿腹侧中脑组织，而对照组（n = 5）接受未添加胶质细胞系源性神经营养因子的新鲜移植物。通过行为分析（旋转测量法）和酪氨酸羟化酶免疫组织化学评估移植成功率。酪氨酸羟化酶染色切片的细胞计数显示，与对照移植物相比，在冬眠期间暴露于胶质细胞系源性神经营养因子的移植物中酪氨酸羟化酶阳性神经元在统计学上有显著增加。此外，与胶质细胞系源性神经营养因子新鲜移植物组相比，胶质细胞系源性神经营养因子冬眠移植物组的纤维密度在统计学上有显著增强。移植后三周的行为分析显示，与对照移植物相比，移植了胶质细胞系源性神经营养因子移植物的动物中安非他明诱导的旋转在统计学上有显著减少。这些发现表明，在移植前将多巴胺能细胞储存在含有胶质细胞系源性神经营养因子的培养基中可提高移植物存活率、移植物衍生的纤维生长以及成年宿主的行为恢复。这一观察结果对提高神经移植治疗帕金森病的疗效具有潜在意义。
