Krobert K, Lopez-Colberg I, Cunningham L A
Department of Pharmacology, University of New Mexico School of Medicine, Albuquerque 87131, USA.
Exp Neurol. 1997 Jun;145(2 Pt 1):511-23. doi: 10.1006/exnr.1997.6483.
Intrastriatal grafting of dopamine-rich embryonic ventral mesencephalon (VM) is a potential therapeutic treatment for Parkinson's disease. However, it has been suggested that the efficacy of this procedure might be improved by enhancing the survival and/or degree of neurite outgrowth by the grafted VM, since these parameters are currently suboptimal. In the present study, we tested the ability of astrocytes retrovirally transduced to produce recombinant brain-derived neurotrophic factor (BDNF) to enhance the survival and/or function of embryonic VM in the unilateral 6-hydroxydopamine (6-OHDA) lesioned rat, a well-characterized rodent model of Parkinson's disease. In culture, primary astrocytes derived from Postnatal Day 0 (P0) rat striatum and transduced with the BDNF vector increased the survival of Embryonic Day 15 (E15) dopaminergic VM neurons by approximately threefold and reduced the loss of dopaminergic neurons following 6-OHDA treatment by approximately 20%. The cultured astrocytes were then mixed 1:1 with freshly dissociated E15 VM and co-grafted into the dopamine-denervated striatum. Unexpectedly, the control nontransduced astrocytes reduced the survival of dopaminergic neurons by 60% and restricted the pattern of neurite outgrowth by the co-grafted VM, compared to grafts of VM alone at 7 weeks postgrafting. These effects were paralleled by an attenuated rate and degree of behavioral recovery. The detrimental effects of the control astrocytes were partially reversed when the astrocytes were transduced to express BDNF, although dopaminergic neuron survival was still reduced by 30% compared to that within VM-only grafts. To begin to assess whether the detrimental effects of the astrocytes were related to the maturational state of the cultured astrocytes, astrocytes were obtained from E18 striatum and maintained in short-term culture (9 days vs several weeks for P0 cultures) prior to co-grafting with VM. Interestingly, the younger astrocytes did not reduce graft survival and allowed for better graft integration. These results suggest that primary astrocytes maintained in long-term culture are detrimental to embryonic neural grafts, an effect that is not completely overcome by expression of recombinant BDNF, and that astrocyte age may be an important consideration in the use of these cells as CNS gene delivery vehicles.
将富含多巴胺的胚胎腹侧中脑（VM）移植到纹状体内是治疗帕金森病的一种潜在疗法。然而，有人提出，通过提高移植的VM的存活率和/或神经突生长程度，可能会改善该手术的疗效，因为目前这些参数并不理想。在本研究中，我们测试了经逆转录病毒转导以产生重组脑源性神经营养因子（BDNF）的星形胶质细胞增强单侧6-羟基多巴胺（6-OHDA）损伤大鼠胚胎VM存活率和/或功能的能力，该大鼠是一种特征明确的帕金森病啮齿动物模型。在培养过程中，源自出生后第0天（P0）大鼠纹状体并经BDNF载体转导的原代星形胶质细胞使胚胎第15天（E15）多巴胺能VM神经元的存活率提高了约三倍，并使6-OHDA处理后多巴胺能神经元的损失减少了约20%。然后将培养的星形胶质细胞与新鲜解离的E15 VM按1:1混合，并共同移植到多巴胺去神经支配的纹状体中。出乎意料的是，与仅移植VM 7周后的情况相比，未转导的对照星形胶质细胞使多巴胺能神经元的存活率降低了60%，并限制了共同移植的VM的神经突生长模式。行为恢复的速度和程度也相应减弱。当星形胶质细胞转导表达BDNF时，对照星形胶质细胞的有害作用部分得到逆转，尽管与仅移植VM相比，多巴胺能神经元的存活率仍降低了30%。为了开始评估星形胶质细胞的有害作用是否与培养的星形胶质细胞的成熟状态有关，在与VM共同移植之前，从E18纹状体中获取星形胶质细胞并进行短期培养（9天，而P0培养为几周）。有趣的是，较年轻的星形胶质细胞不会降低移植存活率，并允许更好的移植整合。这些结果表明，长期培养的原代星形胶质细胞对胚胎神经移植有害，重组BDNF的表达并不能完全克服这种影响，并且在将这些细胞用作中枢神经系统基因传递载体时，星形胶质细胞的年龄可能是一个重要的考虑因素。
