An Ran, Li Yadong, Niu Xiaojun, Yu Hongtao
Department of Chemistry, Jackson State University, Jackson, MS 39217, USA.
Int J Environ Res Public Health. 2008 Jun;5(2):99-103. doi: 10.3390/ijerph5020099.
Liquid crystals (LCs) are typically elongated organic molecules with a non-uniform distribution of electrical charges leading to a dipole. LCs are widely used in displays of computers and other electronic devices. The rapid obsolescence rate of electronics results in large amounts of liquid crystal displays (LCDs) entering the environment. Data on health effects of LCs on living creatures are currently limited to some acute toxicity tests by a few major LC manufacturers. These tests concluded that the vast majority of LCs are not acutely toxic. Since the amount of LCs in electronic devices is very small, the health effects of LCs at low concentrations or doses become important. Catfish were used as the test animals in this study. Four major enzymes of the fish's antioxidant defense system catalase (CAT), superoxide dismutase (SOD), selenium-dependent glutathione peroxidase (Se-GPx), and glutathione-S-transferase (GST) were chosen as biomarkers to examine effects of LCs, which were taken from obsolete laptop personal computers made in the early 1990s. The catfish were fed with food containing different contents of LCs for 40 days. Activities of the four chosen enzymes in fish livers were assayed. The results showed that there were significant inductions of CAT, SOD, and Se-GPx activities in response to the LC doses. The plots of the enzyme activities versus LC doses suggested an occurrence of oxidative stress when the dose reached about 20 microg LC/g fish.d. It was concluded that LCs can cause pollutant-induced stress to catfish at low doses. CAT, SOD and Se-GPx are effective biomarkers to give early warning on potential health effects of LCs on some aquatic lives including catfish.
液晶（LCs）通常是细长的有机分子，其电荷分布不均匀，从而产生偶极子。液晶广泛应用于计算机和其他电子设备的显示屏中。电子产品的快速淘汰率导致大量液晶显示器（LCDs）进入环境。目前，关于液晶对生物健康影响的数据仅限于少数几家主要液晶制造商进行的一些急性毒性测试。这些测试得出的结论是，绝大多数液晶没有急性毒性。由于电子设备中的液晶含量非常少，低浓度或低剂量液晶对健康的影响就变得很重要。本研究以鲶鱼作为实验动物。选取鱼类抗氧化防御系统的四种主要酶，即过氧化氢酶（CAT）、超氧化物歧化酶（SOD）、硒依赖性谷胱甘肽过氧化物酶（Se-GPx）和谷胱甘肽-S-转移酶（GST）作为生物标志物，以检测液晶的影响，这些液晶取自20世纪90年代初生产的过时笔记本电脑。给鲶鱼喂食含有不同含量液晶的食物，持续40天。检测鱼肝脏中所选的四种酶的活性。结果表明，随着液晶剂量的增加，CAT、SOD和Se-GPx的活性有显著诱导。酶活性与液晶剂量的关系图表明，当剂量达到约20微克液晶/克鱼·天左右时，会出现氧化应激。研究得出结论，低剂量的液晶会对鲶鱼造成污染物诱导的应激。CAT、SOD和Se-GPx是有效的生物标志物，可对液晶对包括鲶鱼在内的一些水生生物的潜在健康影响发出早期预警。
