莱菔硫烷对急性一氧化碳中毒大鼠脑组织神经细胞线粒体损伤的治疗作用

Therapeutic effect of sulforaphane on neuronal mitochondrial damage of brain tissue in rats with acute carbon monoxide poisoning

目的 探讨急性一氧化碳（CO）中毒后脑组织神经细胞线粒体超微结构和功能的损伤机制,明确不同剂量莱菔硫烷（sulforaphane,SFP）对急性CO中毒大鼠海马神经元的保护作用.方法 150只成年健康SD大鼠按数字表法随机分为正常对照组（30只）、CO中毒组（30只）和SFP治疗组90只.用高压氧舱吸入法建立急性CO中毒动物模型,用透射电镜观察大鼠脑组织神经细胞线粒体超微结构,JC-1荧光探针检测线粒体膜电位（MFI）变化,用免疫组化和定量RT-PCR法检测干预前后大鼠脑组织核转录因子红细胞相关因子-2 （Nrf-2）、硫氧还蛋白-1（Trx-1）及其mRNA的表达水平.结果 CO中毒可引起大鼠脑组织神经细胞线粒体超微结构受损,SFP能明显减轻CO中毒后神经细胞线粒体损伤程度.CO中毒后大鼠脑组织MFI值明显下降,SFP给药后3～7 d,神经细胞的MFI值虽有下降,但其水平明显高于同时间点CO中毒组（P＜0.05）.与正常对照组相比,CO中毒大鼠脑组织中Nrf-2和Trx-1蛋白及其mRNA的表达水平略有增加,差异有统计学意义（P ＜0.05）;SFP治疗后其表达水平明显增加,与同一时间点CO组比较,差异有统计学意义（P＜0.05）.结论 CO中毒早期应用中等或高剂量的SFP能明显改善神经细胞线粒体结构和功能,增强细胞抗氧化应激能力,对急性CO中毒引起的脑损伤有积极的保护作用.

Objective To explore the mechanism of ultrastructural and functional impairment of mitochondria and the protective effect of sulforaphane （SFP） at different dosages on hippocampus neurons in rats after acute carbon monoxide（CO）poisoning.Methods One hundred and fifty adult healthy SD rats were randomly divided into the normal control group,the CO poisoning group and the SFP treatment group.The rat model of CO poisoning was established through exposure to CO in a hyperbaric chamber.The uhrastructural changes of mitochondria in nerve cells of the brain tissue were observed by transmission electron microscopy （TEM）.Mitochondrial membrane potential （MFI） was detected with JC-1 fluorescent probe,and the expressions of Nrf-2 and Trx-1 proteins and mRNA were evaluated by immunohistochemistry and quantitative RT-PCR before and after intervention.Results CO poisoning could induce impairment of mitochondria ultrastructure in neurocytes in the brain tissue.SFP could obviously alleviate the damage of mitochondria ultrastructure.The MFI level in the brain tissue was obviously reduced in rats after CO exposure.Though MFI level was decreased 3 to 7 days after SFP administration,its level was significantly higher than that of the CO poisoning group at the same time point （P ＜0.05）.As compared with those in the normal control group,the expression levels of Nrf-2 and Trx-1 proteins as well as their mRNA in the CO poisoning group were slightly increased （P ＜ 0.05）.After treatment with SFP,the expressions of both the proteins and mRNA were obviously increased,and there was significant difference when compared with that of the CO poisoning group at the same time point （P ＜0.05）.Conclusion Early administration of either moderate or high dose SFP could efficiently improve mitochondrial structure and function,enhance anti-oxidative stress of cells,thus exerting a positive effect against brain damage induced by acute CO poisoning.