Magnetometric Evaluation of Toxicity of Gallium Arsenide to Lungs and Alveolar Macrophage

砷化镓(GaAs)导致了发光二极管和半导体激光器等电光器件的发展。一些报告指出，肺部接触砷化镓粉尘是一种潜在的职业健康危害。在体肺毒性、免疫毒性和对卟啉代谢的影响已在暴露于GaAs的动物身上表现出来。经气管内注入磁性颗粒的动物胸腔磁化后的磁场迅速下降，被认为是松弛。这一现象表明，由于巨噬细胞中吞噬的氧化铁颗粒的随机旋转，肺部磁化后剩余磁场迅速下降。在实验的前半部分，观察了氧化铁的延迟松弛和清除。在实验的后半部分，将附着在玻璃上的肺泡巨噬细胞暴露于含或不含含20mug/mlGaAs的氧化铁60mug培养液中。在不含砷化镓介质的样品中观察到了快速弛豫，而在含砷化镓的样品中观察到了延迟弛豫。砷化镓对松弛的损伤呈剂量依赖性。由于在培养液中加入氧化镓并不影响细胞的松弛，因此认为砷会影响细胞的松弛。细胞释放乳酸脱氢酶(LDH)是细胞毒性的经典测试，也表明了砷对巨噬细胞的毒性作用。透射电子显微镜下可见染毒巨噬细胞的细胞膜、细胞器和细胞核发生改变。体内细胞磁学测量可用于评价化学物质对吞噬细胞的毒性。

Gallium arsenide (GaAs) has led to the development of electro-optical devices such as light-emitting diodes and semiconductor lasers. Several reports point to pulmonary exposure to GaAs dust as a potential occupational health hazard. In vivo pulmonary toxicity, immuno toxicity and effects on porphyrin metabolism have been demons trated in animals exposed to GaAs.A rapid decrease in the magnetic field after magnetization of the thorax of animals intratracheally instilled with magnetic particles has been noted and designated as "relaxation". This phenomenon indicates a rapid decrease of remanent magnetic field following magnetization of the lungs due to random rotation of phagocytosed iron oxide particles in macrophages. In the first part of study, delayd relaxation and clearance of iron oxide were observed in rabbits exposed to GaAs.In the latter part of study, alveolar macrophages adhered to glass in the bottom of wells were exposed to iron oxide 60mug with or without GaAs20mug/ml in culture medium. Rapid relaxation was observed in the sample of GaAs free medium, whereas relaxation for the specimen with GaAs was delayd. GaAs impaired relaxation dose-dependently. Since addition of Ga_2O_3 into the medium did not affect relaxation, arsenic is considered affecting relaxation.LDH release from cells, classical test for cellular toxicity, also indicated toxic effect of GaAs on macrophages. Transmission electron micros copy revealed alterations of cell membrane, organelles and nucleus in macrophages exposed to GaAs.In vivo cellular magnetometry appears applicable to evaluate toxicity of chemical substance on phagocytic cells.