Minami Keiichi, Maniratanachote Rawiwan, Katoh Miki, Nakajima Miki, Yokoi Tsuyoshi
Drug Metabolism and Toxicology, Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa 920-1192, Japan.
Mutat Res. 2006 Jan 31;603(1):64-73. doi: 10.1016/j.mrgentox.2005.10.008. Epub 2005 Dec 5.
DNA microarray technology was developed as a tool for simultaneously measuring a number of gene expression changes, and has been applied for investigations of toxicity assessments of chemicals. In this study, we used a typical hepatotoxicant, thioacetamide (TA), to find correlations between the extent of hepatotoxicity and certain gene expression patterns or specific gene expression profiles. TA was intraperitoneally administered at high (400 mg/kg), medium (150 mg/kg) or low (50 mg/kg) dose (four rats per group) and then the serum and liver were collected at the indicated time (6, 12, 24, 36 and 48 h). Serum biochemical markers were measured and hepatic mRNA expression profiles were analyzed by a DNA microarray. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were increased by TA-administration in a dose-dependent manner and reached the maximum at 24h. Hierarchical clustering analysis of all dosage groups revealed in 2 major clusters, distinguished by an early (6 and 12h) and a late (24, 36 and 48 h) phase. The early and late phase clusters were sorted in time- and dose-dependent manners. The major gene expression profile obtained by quality-threshold (QT) clustering analysis showed the same maximal toxic time as that estimated by the serum biochemical markers. The individual expression profiles of the candidate genes selected in our previous studies and the simultaneous gene expression patterns measured by five typical hepatotoxicants including TA also reflected the hepatotoxicity of TA. These findings suggest that the potential toxic effects appearing as gene expression changes are independent of the dosage of TA. This study suggested that the major gene expression profile estimated by QT clustering would be a sensitive marker of hepatotoxicity.
DNA微阵列技术作为一种可同时测量多个基因表达变化的工具而被开发出来，并已应用于化学物质毒性评估的研究中。在本研究中，我们使用一种典型的肝毒性物质硫代乙酰胺（TA），以寻找肝毒性程度与某些基因表达模式或特定基因表达谱之间的相关性。将TA以高剂量（400mg/kg）、中剂量（150mg/kg）或低剂量（50mg/kg）腹腔注射给药（每组4只大鼠），然后在指定时间（6、12、24、36和48小时）采集血清和肝脏。检测血清生化标志物，并通过DNA微阵列分析肝脏mRNA表达谱。TA给药后，血清天冬氨酸转氨酶（AST）和丙氨酸转氨酶（ALT）呈剂量依赖性升高，并在24小时达到最大值。所有剂量组的层次聚类分析显示分为2个主要簇，以早期（6和12小时）和晚期（24、36和48小时）区分。早期和晚期簇按时间和剂量依赖性方式排序。通过质量阈值（QT）聚类分析获得的主要基因表达谱显示出与血清生化标志物估计的最大毒性时间相同。我们之前研究中选择的候选基因的个体表达谱以及包括TA在内的五种典型肝毒性物质同时测量的基因表达模式也反映了TA的肝毒性。这些发现表明，作为基因表达变化出现的潜在毒性作用与TA的剂量无关。本研究表明，通过QT聚类估计的主要基因表达谱将是肝毒性的敏感标志物。
