Student Research Committee, Ardabil University of Medical Sciences, Ardabil, Iran.
Department of Biochemistry, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran.
Neurotox Res. 2017 Nov;32(4):624-638. doi: 10.1007/s12640-017-9777-y. Epub 2017 Jul 11.
2,4-dicholorophenoxy acetic acid (2,4-D) is a worldwide-known hormone herbicide. However, there are increasing concerns about its exposure and risks of developing pathological conditions for the peripheral nervous system. The aim of this study was to investigate the mechanism(s) involved in the toxicity of 2,4-D on peripheral nerve's cellular components. The epi/perineural and Schwann cells and a total of three cell lines were treated with 2,4-D. The viability of cells at different doses of 2,4-D was measured by MTT assay. The cell cycle analyses, cumulative cell counting, fluorescent staining, antioxidant and caspase enzymes activity were examined on epi/perineural and Schwann cells. The epi/perineural cells were assessed as having biological macromolecular changes. Some tight junction-related genes and proteins were also tested on explants of 2,4-D treated epi/perineural tissue. The viability of 2,4-D treated cells was reduced in a dose-dependent manner. Reduced growth rate and G1 cell cycle arrest were verified in 2,4-D treated epi/perineural and Schwann cells. The use of staining methods (acridine orange/ethidium bromide and DAPI) and caspase 3/7 activity assay along with malondialdehyde, glutathione peroxidase, and superoxide dismutase activity assays indicated the apoptotic and oxidant effects of 2,4-D on epi/perineural and Schwann cells. Data obtained from FTIR revealed changes in epi/perineural proteins and cell membrane lipids. Additionally, claudin-1, occludin, and ZO-1 gene/protein expression profiles were significantly reduced in 2,4-D-treated epi/perineural pieces. Our data indicated that oxidative stress, apoptosis of epi/perineural and Schwann cell and impaired blood-nerve barrier may have contributed to nerve damage following 2,4-D exposure.
2,4-二氯苯氧乙酸（2,4-D）是一种世界范围内广泛使用的激素型除草剂。然而，人们越来越关注其暴露和对外周神经系统产生病理状况的风险。本研究旨在探讨 2,4-D 对周围神经细胞成分毒性的作用机制。将神经外膜/神经周围细胞和雪旺细胞以及总共三种细胞系用 2,4-D 处理。通过 MTT 测定法测量不同剂量 2,4-D 下细胞的活力。对神经外膜/神经周围细胞进行细胞周期分析、累积细胞计数、荧光染色、抗氧化和半胱天冬酶酶活性检测。评估神经外膜/神经周围细胞的生物大分子变化。还在 2,4-D 处理的神经外膜组织的外植体上测试了一些紧密连接相关基因和蛋白质。2,4-D 处理的细胞活力呈剂量依赖性降低。在 2,4-D 处理的神经外膜/神经周围细胞和雪旺细胞中证实了生长速度降低和 G1 细胞周期停滞。使用染色方法（吖啶橙/溴化乙锭和 DAPI）和 caspase 3/7 活性测定以及丙二醛、谷胱甘肽过氧化物酶和超氧化物歧化酶活性测定表明 2,4-D 对神经外膜/神经周围细胞和雪旺细胞具有凋亡和氧化作用。FTIR 获得的数据显示神经外膜蛋白和细胞膜脂质发生变化。此外，2,4-D 处理的神经外膜组织中 Claudin-1、Occludin 和 ZO-1 基因/蛋白表达谱显著降低。我们的数据表明，氧化应激、神经外膜/神经周围细胞和雪旺细胞凋亡以及血神经屏障受损可能是 2,4-D 暴露后神经损伤的原因。
