Chang Jing, Li Jitong, Wang Huili, Wang Yinghuan, Guo Baoyuan, Yin Jing, Hao Weiyu, Li Wei, Li Jianzhong, Xu Peng
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China; University of Chinese Academy of Sciences, Yuquan RD 19 a, Beijing, 100049, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing RD 18, Beijing 100085, China.
Environ Pollut. 2016 Nov;218:965-972. doi: 10.1016/j.envpol.2016.08.045. Epub 2016 Aug 25.
Lambda-cyhalothrin (LCT) is a widely used pyrethroid with neurotoxicity. However, little is known about the toxicokinetics of LCT in reptiles. In this study, the absorption, distribution, metabolism and excretion of LCT in Chinese lizards (Eremias Argus) were determined following a single dose (10 mg kg) treatment. In the liver, brain, gonads and skin, LCT levels peaked within several hours and then decreased rapidly. However, the concentration of LCT gradually increased in the fat tissue. More than 90% of the LCT dose was excreted in the faeces. One LCT metabolite, 3-phenoxybenzoic acid (PBA), was detected in lizard plasma and tissues. PBA preferentially accumulates in the brain and plasma. The half-life of PBA in the brain was 3.2 days, which was 35.4-fold greater than that of LCT. In the plasma, the concentration of PBA was significantly higher than that of LCT. The bioaccumulation of LCT in tissues was enantioselective, and the enantiomeric fractions (EF) ranged from 0.72 to 0.26. The preferential accumulation of enantiomers changed according to exposure time, but the reasons behind this phenomenon were not clear. For pathological analysis, vacuolation of the cytoplasm and large areas of necrosis were observed in the liver sections after 168 h of dosing. The liver tissues exhibited both decreases in the hepatosomatic index and histopathological lesions during the exposure period. In this study, the effect concentration of LCT in lizards was 200-fold lower than its LD value used in risk assessments for birds. These results may provide additional information for the risk assessment of LCT for reptiles and indicate that birds may not be an ideal surrogate for reptile toxicity evaluation.
高效氯氟氰菊酯（LCT）是一种广泛使用的拟除虫菊酯，具有神经毒性。然而，关于LCT在爬行动物中的毒代动力学知之甚少。在本研究中，对中国石龙子（丽斑麻蜥）单次给药（10mg/kg）后LCT的吸收、分布、代谢和排泄情况进行了测定。在肝脏、大脑、性腺和皮肤中，LCT水平在数小时内达到峰值，然后迅速下降。然而，LCT在脂肪组织中的浓度逐渐升高。超过90%的LCT剂量通过粪便排出。在石龙子的血浆和组织中检测到一种LCT代谢物，3-苯氧基苯甲酸（PBA）。PBA优先在大脑和血浆中蓄积。PBA在大脑中的半衰期为3.2天，比LCT的半衰期长35.4倍。在血浆中，PBA的浓度显著高于LCT。LCT在组织中的生物蓄积具有对映体选择性，对映体分数（EF）范围为0.72至0.26。对映体的优先蓄积随暴露时间而变化，但这种现象背后的原因尚不清楚。病理分析显示，给药168小时后肝脏切片出现细胞质空泡化和大面积坏死。在暴露期间，肝脏组织的肝体指数下降，且出现组织病理学损伤。在本研究中，LCT对石龙子的效应浓度比鸟类风险评估中使用的LD值低200倍。这些结果可能为LCT对爬行动物的风险评估提供更多信息，并表明鸟类可能不是评估爬行动物毒性的理想替代物。
