Kaur Parvinder, Heggland Ingrid, Aschner Michael, Syversen Tore
Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology, Olav Kyrresgt. 3, N-7489 Trondheim, Norway.
Neurotoxicology. 2008 Nov;29(6):978-87. doi: 10.1016/j.neuro.2008.06.004. Epub 2008 Jun 20.
The ability of docosahexaenoic acid (DHA) to modulate methylmercury (MeHg)-induced neurotoxicity was investigated in primary astrocytes and neurons from the cerebellum. Gas chromatography measurements indicated increased DHA content in both cell types after 24h supplementation. After individual or combined treatment with MeHg (10microM) and DHA (30 and 90microM), the cell-associated MeHg measurements were done using (14)C-labelled MeHg. In addition, mitochondrial activity was evaluated by MTT reduction, glutathione (GSH) content was measured with the fluorescent indicator monochlorobimane (MCB) and reactive oxygen species (ROS) were detected with the fluorescent indicator-chloro methyl derivative of di-chloro di-hydro fluorescein diacetate (CMH(2)DCFDA). For all the tested treatments, i.e. DHA, MeHg or DHA+MeHg treatment, the neurons differed significantly (p<0.001) from astrocytes exhibiting increased ROS production and decreased MTT activity. After MeHg and 30microM DHA treatment there were no changes in MTT or GSH content but significant decrease (p<0.001) in ROS was observed in both the cell types when compared to MeHg alone. The cell-associated MeHg measurements indicated reduced MeHg-accumulation in both cell types (p<0.05) upon 30microM DHA exposure. Taken together, this study, for the first time establishes that DHA pretreatment effectively reduces cell-associated MeHg and prooxidant response from MeHg in both cerebellar astrocytes and neurons and thus supports the hypothesis that fish-derived nutrients offer possible neuroprotection from MeHg.
在来自小脑的原代星形胶质细胞和神经元中，研究了二十二碳六烯酸（DHA）调节甲基汞（MeHg）诱导的神经毒性的能力。气相色谱测量表明，补充24小时后，两种细胞类型中的DHA含量均增加。在用MeHg（10微摩尔）和DHA（30和90微摩尔）单独或联合处理后，使用（14）C标记的MeHg进行细胞相关的MeHg测量。此外，通过MTT还原评估线粒体活性，用荧光指示剂单氯双马来酰亚胺（MCB）测量谷胱甘肽（GSH）含量，并用荧光指示剂二氯二氢荧光素二乙酸酯的氯甲基衍生物（CMH₂DCFDA）检测活性氧（ROS）。对于所有测试的处理，即DHA、MeHg或DHA+MeHg处理，神经元与星形胶质细胞有显著差异（p<0.001），表现为ROS产生增加和MTT活性降低。在MeHg和30微摩尔DHA处理后，MTT或GSH含量没有变化，但与单独使用MeHg相比，两种细胞类型中的ROS均显著降低（p<0.001）。细胞相关的MeHg测量表明，在30微摩尔DHA暴露后，两种细胞类型中的MeHg积累均减少（p<0.05）。综上所述，本研究首次证实，DHA预处理可有效降低小脑星形胶质细胞和神经元中细胞相关的MeHg以及MeHg的促氧化反应，从而支持了鱼类来源的营养物质可能对MeHg具有神经保护作用这一假说。
