Study of the potential toxicity of adrenaline to neurons, using the SH-SY5Y human cellular model

Abstract Prolonged overexposure to catecholamines causes toxicity, usually credited to continuous adrenoceptor stimulation, autoxidation, and the formation of reactive pro-oxidant species. Non-differentiated SH-SY5Y cells were used to study the possible contribution of oxidative stress in adrenaline (ADR)-induced neurotoxicity, as a model to predict the toxicity of this catecholamine to peripheral nerves. Cells were exposed to several concentrations of ADR (0.1, 0.25, 0.5 and 1mM) and two cytotoxicity assays [lactate dehydrogenase (LDH) release and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction] were performed at several time-points (24, 48, and 96h). The cytotoxicity of ADR was concentration- and time-dependent in both assays, since the lowest concentration tested (0.1mM) also caused significant cytotoxicity at 96h. N-acetyl-cysteine (1mM), a precursor of glutathione synthesis, prevented ADR-induced toxicity elicited by 0.5mM and 0.25mM ADR following a 96-h exposure, while the antioxidant Tiron (100µM) was non-protective. In conclusion, ADR led to mitochondrial distress and ultimately cell death in non-differentiated SH-SY5Y cells, possibly because of ADR oxidation products. The involvement of such processes in the catecholamine-induced peripheral neuropathy requires further analysis.

摘要 长期过度暴露于儿茶酚胺类物质会引发毒性，该毒性通常归因于持续的肾上腺素能受体刺激、自氧化反应以及活性促氧化物种的生成。本研究以未分化的SH-SY5Y细胞（SH-SY5Y cells）为模型，探究氧化应激在肾上腺素（ADR）诱导的神经毒性中的潜在作用，并以此预测该儿茶酚胺对外周神经的毒性。研究人员将细胞暴露于梯度浓度的肾上腺素（ADR：0.1、0.25、0.5和1mM）中，并在24、48及96小时三个时间点开展两种细胞毒性检测实验：乳酸脱氢酶（LDH）释放实验与3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四氮唑蓝（MTT）还原实验。两种实验均显示，肾上腺素的细胞毒性呈浓度与时间依赖性：即便最低受试浓度（0.1mM）在96小时时也引发了显著的细胞毒性。1mM的谷胱甘肽合成前体N-乙酰半胱氨酸，可阻断0.5mM与0.25mM肾上腺素经96小时暴露所诱导的细胞毒性；而100µM的抗氧化剂钛铁试剂（Tiron）则未表现出保护作用。综上，未分化的SH-SY5Y细胞中，肾上腺素可引发线粒体应激并最终导致细胞死亡，这一现象可能与肾上腺素的氧化产物有关。上述过程在儿茶酚胺诱导的外周神经病变中的具体作用仍需进一步分析。