乐果急性、亚急性暴露对大鼠胆碱酯酶及细胞色素氧化酶影响的研究

Alterations of Acetycholinesterse and Hepatic Cytochrome P450 2B1/2 in Dimethoate-Induced Rats

对6周龄雄性SD大鼠分别单次灌胃给予50％（LD50）的乐果、连续5d灌胃给予20％（LD50）的乐果，观察给药后至屠宰前大鼠的急性、亚急性毒性反应。采用丁酰硫代胆碱法测定红细胞、血清和脑组织中的胆碱酯酶；采用定量RT-PCR法测定试验大鼠肝脏中细胞色素氧化酶8个亚型的表达量。结果表明：供试大鼠用药后不同时间出现了呕吐、流泪、流涎、震颤等典型的有机磷药物中毒症状。红细胞、血清和脑组织中的胆碱酯酶均明显降低，以试验组和对照组脑组织中胆碱酯酶差异最为显著，急性暴露组大鼠脑组织中的胆碱酯酶降低80．12％，亚急性＋暴露组大鼠脑组织中的胆碱酯酶降低93．13％。试验组大鼠细胞色素氧化酶中CYP2B1／2亚型的表达量明显增加。为对照组大鼠表达量的4～8倍。

Different high dosages of dimethoate were administered by gavage once and five times to male wistar rats. Acute and subacute toxicity reaction was observed 6 hours after the last administration. The activity of acetycholinesterse of red blood cell, blood serum and brain was assayed by the method of butyrylthiocholine and expression level of some subtypes of CYP was detected by a reverse transcription polymerase chain reaction. Vomiting, dacryrrhea, sialorrhea and tremulation of muscle appeared. Acetylcholinesterase of red blood cell, blood serum and brain of rats in the experimental group decreased significantly. Acetylcholinesterase of brain decreased most significantly, by 80.12% in the acute exposure experiment and by 93.13% in the subacute exposure experiment. The expression level of CYP2B1/2 mRNA in experimental group increased significantly, 4 - 8 times of that in control group.