Grunnet Niels, Tygstrup Niels, Dich John
Department of Medical Biochemistry and Genetics, University of Copenhagen, Panum Institute, Copenhagen, Denmark.
Pharmacol Toxicol. 2003 Sep;93(3):135-41. doi: 10.1034/j.1600-0773.2003.930305.x.
To evaluate the effect of acetaminophen pretreatment and growth factors on acetaminophen hepatotoxicity in cultured rat hepatocytes, rat hepatocytes in primary culture were exposed to acetaminophen 8 mM after pretreatment with either acetaminophen 1 mM, treatment with growth factors (EGF and HGF), or no treatment. Growth response was measured by changes in DNA, [3H]thymidine incorporation and mRNA of growth related proteins, cell damage by leakage of LDH to the medium and changes in ATP, and protection against toxicity by changes in glutathione, cytochrome p450 and the expression of glutathione-S-transferase and Cyp1A2. Pretreatment with acetaminophen induced growth response, weaker than that of growth factors, but pretreatment and growth factors reduced cell damage equally effectively. Glutathione and glutathione-S-transferase increased more by growth factors than by pretreatment, but both conditions reduced Cyp1A2 to near zero. Pretreatment and growth factors protect against acetaminophen toxicity by suppressing the expression of Cyp1A2, thereby reducing the production of the intermediate N-acetyl-p-benzoquinone imine (NAPQI). Suppression of Cyp1A2 expression by pretreatment is assumed to be due to a growth-stimulating effect of low concentrations of acetaminophen.
为评估对乙酰氨基酚预处理及生长因子对培养的大鼠肝细胞中对乙酰氨基酚肝毒性的影响，将原代培养的大鼠肝细胞在分别用1 mM对乙酰氨基酚预处理、用生长因子（表皮生长因子和肝细胞生长因子）处理或不处理后，暴露于8 mM对乙酰氨基酚。通过DNA变化、[3H]胸腺嘧啶核苷掺入及生长相关蛋白的mRNA来测量生长反应，通过乳酸脱氢酶泄漏到培养基中的情况及ATP变化来评估细胞损伤，并通过谷胱甘肽、细胞色素P450以及谷胱甘肽-S-转移酶和Cyp1A2表达的变化来评估对毒性的保护作用。对乙酰氨基酚预处理可诱导生长反应，但其作用弱于生长因子，但预处理和生长因子对减少细胞损伤的效果相同。生长因子使谷胱甘肽和谷胱甘肽-S-转移酶的增加幅度大于预处理，但两种情况均使Cyp1A2降至接近零。预处理和生长因子通过抑制Cyp1A2的表达来预防对乙酰氨基酚毒性，从而减少中间产物N-乙酰-p-苯醌亚胺（NAPQI）的产生。低浓度对乙酰氨基酚的生长刺激作用被认为是预处理导致Cyp1A2表达受抑制的原因。
