星形胶质细胞在脂多糖诱导的多巴胺能神经元损伤中的作用

The role of astrocyte in the lipopolysaccharides-induced damage of dopaminergic neurons

目的探讨星形胶质细胞在不同浓度脂多糖诱导的多巴胺能神经元损伤中的作用。方法在第3代星形胶质细胞中加入终浓度为0、0．1、10．0mg／L脂多糖作用24h，收集条件培养液。采用L-抗坏血酸-2-磷酸酯倍半镁盐和人成纤维生长因子促进孕12d的SD大鼠中脑前体细胞扩增、分化为多巴胺能神经元，通过阿糖胞苷抑制胶质细胞的增殖，建立高比例多巴胺能神经元的纯神经元培养体系。在此基础上，利用Transwell双室培养系统建立星形胶质细胞和纯神经元共培养体系，观察脂多糖、条件培养液和星形胶质细胞对纯神经元体系中多巴胺能神经元存活及酪氨酸羟化酶mRNA表达的影响。结果脂多糖对纯神经元体系中的多巴胺能神经元有损伤作用，并呈剂量依赖性。与单用脂多糖比较，条件培养液显著升高多巴胺能神经元存活，其中0．1mg／L脂多糖刺激组多巴胺能神经元的存活能力最强，其次为10．0mg／L组，最后为0mg／L组。与条件培养液组比较，共培养体系中多巴胺能神经元存活能力更高，其中0．1mg／L脂多糖干预后多巴胺能神经元的存活能力最强，随后依次为10．0mg／L、0mg／L、20．0mg／L脂多糖。多巴胺能神经元表达酪氨酸羟化酶mRNA的变化类似多巴胺能神经元数量的变化。结论脂多糖对多巴胺能神经元有损伤作用，并呈剂量依赖性，适度激活的星形胶质细胞对多巴胺能神经元有保护作用，过度激活则削弱了这种保护作用。

Objective To investigate the role of astrocyte in the lipopolysaccharide-induced damage of dopaminergic neurons. Methods After lipopolysaccharide was applied to the third generation of rat astrocytes for 24 hours, supernatants of astrocytes culture were collected. The primary middle-brain dopaminergic neuron-enriched culture systems were obtained by neurobasal and ara-c, coculture system of both astrocytes and neurons was established by transwell inserts. The lipopolysaccharide was administered into neuron-enriched systems and coculture systems and the change of dopaminergic neurons was detected. At the same time, the supernatants of astrocytes were administered into the neuron-enriched systems, and the survival of dopaminergic neurons and the expression of tyrosine hydroxylase mRNA were observed. Results Lipopolysaccharide had a negative effect on the survival of dopaminergic neurons in a concentration-dependent manner. Both astrocytes and supernatants promoted the survival of dopaminergic neurons, and the former was better than the latter. In the preoccupation of existence of astrocytes, low-concentration lipopolysaccharide promoted the survival of dopaminergic neurons, while high-concentration, decreased. The change of the expression of tyrosine hydroxylase mRNA was similar to the survival of dopaminergic neurons. Conclusions Astrocytes play a protective role in the damage of dopaminergic neurons induced by lipopolysaccharide, and suitable activation of astrocytes would increase the protective effect while excessive activation of astrocytes would attenuate the effect.