摘要
目的探讨帕金森病小鼠模型中不同剂量左旋多巴对百草枯毒性作用的影响及相关机制。方法选用不同剂量左旋多巴分别在注射百草枯一定时间的C57BL小鼠(72只)腹腔内注射,利用免疫组化、W estern印迹法等观察黑质部位百草枯沉积和多巴胺能神经元变性以及α-突触核蛋白(-αSyn)聚集,并检测纤维状α-Syn经左旋多巴孵育后其聚集的改变情况。结果在注射百草枯之前腹腔注射小剂量左旋多巴抑制百草枯诱导的黑质部位多巴胺能神经元变性,α-Syn聚集减少;大剂量左旋多巴则促进黑质部位多巴胺能神经元变性。左旋多巴可以解聚已经形成的纤维状α-Syn。结论小剂量左旋多巴竞争性抑制百草枯通过血脑屏障进入中枢神经系统,起到了神经保护作用;大剂量左旋多巴则使已经形成的纤维状α-Syn解聚,出现明显的毒性作用。
Objective To investigate the effects and mechanisms of different doses of levodopa on paraquat-induced neuro-toxicity. Methods 72 C57BL mice were divided into 2 equal groups： acute experiment group and chronic experiment groups. The acute experiment group was re-divided into 2 subgroup： subgroup A to be injected with levodopa of the doses of 0 （distilled water instead）, 10 mg/kg, or 100 mg/kg and then paraquat 30 mg/kg （ levodopa ＋ paaquat）, and then killed 90 minutes after; and subgroup B, to be injected with paraquat 30 mg/kg and then levodopa 0, 10 mg/kg, or 100 mg/kg （paraquat ＋ levodopa）, and then killed 2 hours after. The chronic experiment group was re-divided into 2 subgroups to be injected with levodopa ＋ paraquat or paraquat ＋ levodopa once a week for 3 weeks, and then killed 24 hours after the injection. Fluorescent microscopy was used to observe the fluorescent staining of paraquat in the substantia nigra in the acute experiment group and the fluorescent staining of tyrosine hydroxylase （TH） in the substantia nigra in the chronic experiment group, in the chronic experiment group Western blotting was used to examine the protein expression of TH ; thioflavine double labeling was used to observe the α-synuclein aggregation by immunofluoresence staining and Western blotting. The slices of substantia nigra of the mice in the chronic experiment group treated with distilled water ＋ paraquat were inoculated with or without 250μmol/L levodopa and then underwent thioflavine staining to observe the α-Syn aggregation. Results The paraquat staining was strongly positive in the substantia nigra of the mice in Group A-1, and was decreased gradually in the group! -2 and A-3. The paraquat staining was strongly positive in the substantia nigra of Group B-1 without a significant difference between Group A-1 and Group B- 1, and was not remarkable in Group B-2 and B-3. The TH staining and protein expression in the substantia nigra of Group A-2 were significantly stronger than that of Group
出处
《中华医学杂志》
CAS
CSCD
北大核心
2005年第34期2400-2403,共4页
National Medical Journal of China
基金
上海市重点科委攻关资助项目(44119623)
上海市教委发展基金资助项目(03BK24)
