蛋白酶体抑制剂对小鼠黑质多巴胺神经元的毒性作用

Toxic effect of proteasome inhibitor on nigral dopaminergic neuron in mice

目的:观察蛋白酶体抑制剂对小鼠黑质多巴胺神经元的毒性作用。方法:8周龄C57BL/6小鼠随机分组:磷酸盐缓冲液(PBS组)和lactacystin组,二种制剂分别单侧立体定向注射于中脑前脑束(Middle forebrain bundle);12周龄时灌注取脑分离纹状体,采用HPLC法测多巴胺、5-HT及代谢产物,取中脑观察黑质区多巴胺能神经元变性及包涵体样物质形成情况。结果:Lactacystin组同侧黑质区多巴胺细胞数减少51%,并可见泛素染色阳性的类包涵体样物质形成,同侧纹状体多巴胺(DA)及其代谢产物二羟苯乙酸(DOPAC)、高香草酸(HVA)浓度分别减少52%、46%和51%,而5-羟色胺(5-HT)及5-羟吲哚乙酸(5-HIAA)浓度无改变。结论:蛋白酶体抑制剂可引起选择性黑质区多巴胺能神经元变性,并可能导致细胞内异常蛋白质聚集。

Objective： To observe the toxic effect of proteasome inhibitor on nigral dopaminergic neuron in mice. Methods： Male C57/BL6J mice of age 8 weeks were randomly separated into 2 groups. All mice received a stereotaxic injection into right middle forebrain bundle with either PBS or lactacystin. At the age of 12 weeks, mice were sacrificed. Striate body was rapidly dissected out for biochemical analysis of dopamine （DA）, 3,4-dihydroxyphenylacetic acid （BOPAC）, homovanillic acid （HVA）, serotonin （5-HT）, and 5-hydroxyindolacetic acid （5-HIAA）. The midbrain block received further immunohistology staining of tyrosine hydroxylase（TH） and Ubiquitin. Results： With micro-injection of lactacystin, a 51% decrease of nigral TH-immunopositive cells and intracellular inclusion body formation were found. Biochemical analysis of catecholamine in the striate body showed that lactacystin injection reduced the striatal levels of dopamine and its metabolites DOPAC and HVA by 52%, 46%, and 51%, respectively, while striatal 5-HT and 5-HIAA levels were not affected. Conclusion： Significant loss of dopaminergic neurons and intracellular inclusion body formation can be induced by proteasome inhibitor.