Abstract

Imidacloprid (IMD) is a neonicotinoid insecticide used in large quantities worldwide in both veterinary and agronomic applications. Several studies have shown adverse effects of IMD on non-target organisms, with the liver being identified as the main affected organ. This study aimed to evaluate the effects of IMD on human hepatoblastoma (HepG2) cells. HepG2 were exposed to IMD (0.25–2.0 mM) for 24 and 48 h. IMD treatment resulted in cytotoxicity in the HepG2, inhibiting cell proliferation in a dose- and time-dependent manner, starting at concentrations of 0.5 mM (24 h) and 0.25 mM (48 h), and reducing cell viability from 0.5 mM onwards (24 and 48 h). IMD significantly decreased the mitochondrial membrane potential at both time points investigated (2.0 mM), and also induced damage to the cell membrane, demonstrated by significant dose and time-dependent increases in lactate dehydrogenase (LDH) release from concentrations of 1.0 mM (24 h) and 0.5 mM (48 h) upwards. IMD treatment also increased the production of reactive oxygen and nitrogen species (ROS/RNS) at rates above 50% following 0.5 mM (24 h) or 0.25 mM (48 h) concentrations, and caused a significant decrease in reduced/oxidized glutathione ratio (GSH/GSSG), indicating oxidative stress. Furthermore, the antioxidant dithiothreitol, which reacts with ROS/RNS and acts as a thiol reducing agent, inhibited the cytotoxic effect of IMD. In addition, the metabolite IMD-olefin was more toxic than IMD. Our results indicate that IMD induces cytotoxicity in HepG2 cells and that this effect may be associated with an increase in the generation of ROS/RNS.

摘要

吡虫啉 (IMD) 是一种新烟碱类杀虫剂，在世界范围内大量用于兽医和农业应用。几项研究表明 IMD 对非目标生物体有不利影响，肝脏被确定为主要受影响的器官。本研究旨在评估 IMD 对人肝母细胞瘤 (HepG2) 细胞的影响。HepG2 暴露于 IMD (0.25–2.0 mM) 24 和 48 小时。IMD 处理导致 HepG2 中的细胞毒性，以剂量和时间依赖性方式抑制细胞增殖，从 0.5 mM（24 小时）和 0.25 mM（48 小时）浓度开始，并从 0.5 mM 开始降低细胞活力（24和 48 小时）。IMD 在所研究的两个时间点 (2.0 mM) 显着降低了线粒体膜电位，并且还诱导了对细胞膜的损伤，从 1.0 mM（24 小时）和 0.5 mM（48 小时）的浓度开始，乳酸脱氢酶 (LDH) 释放的显着剂量和时间依赖性增加证明了这一点。在 0.5 mM（24 小时）或 0.25 mM（48 小时）浓度后，IMD 处理还增加了 50% 以上的活性氧和氮物质 (ROS/RNS) 的产生，并导致还原/氧化谷胱甘肽比例显着降低。 GSH / GSSG），表明氧化应激。此外，与 ROS/RNS 反应并作为硫醇还原剂的抗氧化剂二硫苏糖醇可抑制 IMD 的细胞毒作用。此外，代谢物 IMD-烯烃比 IMD 毒性更大。我们的结果表明，IMD 在 HepG2 细胞中诱导细胞毒性，并且这种效应可能与 ROS/RNS 产生的增加有关。