摘要:
五氯酚(pentachlorophenol, PCP)是一种持久性有机污染物,广泛用于灭钉螺、木材防腐、除草剂等方面,由于PCP在环境中的持久性和生物累积性,其对生态环境和人类健康造成潜在危害。本文以鸡肝癌细胞系(chicken hepatoma cells, LMH)为受试对象,探讨了PCP对细胞色素P450(CYP450)和抗氧化系统的影响。MTT结果显示LMH细胞经不同浓度PCP暴露后,呈现出先促进细胞增殖后抑制的J-型曲线,PCP对LMH细胞24 h的半数效应浓度(24 h-EC50)为427.52 μmol·L-1。LMH细胞在1.56、6.25、25、100 μmol·L-1 PCP染毒条件下可增加细胞EROD、MROD、PROD和BFC活性,并可使CYP1A、1B、1C、2H及3A家族基因mRNA表达水平升高。LMH细胞在0.4~100 μmol·L-1 PCP染毒下可显著降低硫酸基转移酶(SULT1B1和SULT 1C1)基因mRNA水平。此外,LMH细胞在6.25、25、100 μmol·L-1 PCP染毒下可引起细胞内ROS升高,同时PCP(1.56~100 μmol·L-1)可显著增加细胞内MDA含量和降低GSH/GSSH比值。这些结果表明细胞色素P450(CYP450)基因及酶活性的变化、细胞内ROS和MDA含量及GSH/GSSH可作为评价LMH细胞PCP毒性效应的敏感性生物标志物。此研究在细胞水平上利用多个评价指标研究PCP对细胞的毒性效应,为PCP环境风险评价提供依据。
Abstract:
Pentachlorophenol (PCP), a persistent organic pollutant, has been used for wood preservation and as a herbicide and insecticide. Due to its persistence in the environment and bioaccumulation, PCP causes potential harm to the ecological environment and human health. In this study, chicken hepatoma cells (LMH) were used to explore the effect of PCP on antioxidant systems and cytochrome P450 (CYP450) levels. The results revealed that 1.56, 6.25, 25 and 100 μmol·L-1 PCP could increase EROD, MROD, PROD and BFC levels, and remarkably upregulated the expressions of CYP1A, 1B, 1C, 2H and 3A families. Data obtained from 24 h-exposure studies demonstrated that 0.4-100 μmol·L-1 PCP could decrease sulfotransferase (SULT1B1 and SULT 1C1) expression levels. When LMH cells were exposed to 6.25, 25, and 100 μmol·L-1 PCP for 24 h, ROS and MDA content increased, while GSH/GSSH deceased significantly. These experimental results showed that PCP exposure could change CYP450 gene expression and activity, ROS and MDA content, and GSH/GSSH ratioin LMH cells. In this view, multiple evaluation indexes should be used to assess the cell toxicity of PCP, which will provide better understanding for PCP risk assessment and mechanism studies.
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