Abstract:

To study the metabolic toxicity of low dose fenitrothion （FNT） exposure on rat BRL cells， and analyze its mechanism through a series of indicators in vitro， the control group and fenitrothion exposure groups（13.78， 27.55 and 55.10 μg·mL^-1） were exposed for 48 h respectively. We observed its effects on the intracellular glucose metabolism level in BRL cells， the expression of insulin sensitivity related proteins and glycogen synthesis related proteins in the signaling pathway of glucose metabolism. The experiment results showed that the viability of BRL cells was significantly inhibited by fenitrothion exposure with an IC₅₀ of 275.5 μg·mL^-1. Exposure to fenitrothion significantly decreased SOD and AchE activities （P<0.01）， increased the content of MDA （P<0.01）， and caused oxidative damage to cells. Exposure to fenitrothion significantly reduced intracellular glycogen content， insulin concentration， and glucokinase content （P<0.01）， increasing insulin resistance. Fenitrothion exposure significantly reduced IRS content， inhibited IRS phosphorylation， and significantly increased AKT， PI3K， GSK-3α and GSK-3β content. Therefore， The mechanism of glucose metabolism toxicity of fenitrothion exposure on BRL cells is that oxidative stress induces insulin resistance and changes the expression of proteins in the signaling pathways related to glucose metabolism.

Key words: fenitrothion, glucose metabolism, metabolic toxicity, signaling pathways

摘要：

为了研究低剂量杀螟硫磷(fenitrothion-O-analog, FNT)暴露对大鼠肝细胞(buffalo rat liver cells,BRL)的代谢毒性，并通过作用于体外的一系列指标分析其作用机制，分别对空白对照组和杀螟硫磷暴露组(13.78、27.55、55.10 μg·mL^-1)暴露48 h，观察其对BRL内糖代谢、胰岛素敏感和糖原合成信号通路中蛋白表达的影响。实验结果表明，杀螟硫磷暴露能够显著抑制BRL细胞的活力，半数抑制浓度（IC₅₀）为275.5 μg·mL^-1。杀螟硫磷暴露使超氧化物歧化酶（superoxide dismutase，SOD）和乙酰胆碱酯酶AchE活力显著降低(P<0.01)，其体内丙二醛（malonaldehyde，MDA）含量显著增加(P<0.01)，引起细胞氧化损伤。杀螟硫磷暴露使其细胞内糖原、胰岛素和葡萄糖激酶含量显著降低(P<0.01)，增加胰岛素抵抗。杀螟硫磷暴露显著下调胰岛素敏感信号通路中IRS的表达，抑制IRS的磷酸化，并显著上调AKT和PI3K的表达，显著上调糖原合成信号通路中GSK-3α和GSK-3β的表达。因此，杀螟硫磷暴露使BRL产生糖代谢毒性的机制是通过氧化应激诱发胰岛素抵抗，从而改变糖代谢相关信号通路中蛋白的表达而实现的。

关键词: 杀螟硫磷, 糖代谢, 代谢毒性, 信号通路