Narita Kazuto, Ishii Yuuki, Vo Phuc Thi Hong, Nakagawa Fumiko, Ogata Shinichi, Yamashita Kunihiko, Kojima Hajime, Itagaki Hiroshi
Department of Chemical and Energy Engineering, Yokohama National University.
Division of Risk Assessment, National Institute of Health Sciences.
J Toxicol Sci. 2018;43(3):229-240. doi: 10.2131/jts.43.229.
Recently, animal testing has been affected by increasing ethical, social, and political concerns regarding animal welfare. Several in vitro safety tests for evaluating skin sensitization, such as the human cell line activation test (h-CLAT), have been proposed. However, similar to other tests, the h-CLAT has produced false-negative results, including in tests for acid anhydride and water-insoluble chemicals. In a previous study, we demonstrated that the cause of false-negative results from phthalic anhydride was hydrolysis by an aqueous vehicle, with IL-8 release from THP-1 cells, and that short-time exposure to liquid paraffin (LP) dispersion medium could reduce false-negative results from acid anhydrides. In the present study, we modified the h-CLAT by applying this exposure method. We found that the modified h-CLAT is a promising method for reducing false-negative results obtained from acid anhydrides and chemicals with octanol-water partition coefficients (LogK) greater than 3.5. Based on the outcomes from the present study, a combination of the original and the modified h-CLAT is suggested for reducing false-negative results. Notably, the combination method provided a sensitivity of 95% (overall chemicals) or 93% (chemicals with LogK > 2.0), and an accuracy of 88% (overall chemicals) or 81% (chemicals with LogK > 2.0). We found that the combined method is a promising evaluation scheme for reducing false-negative results seen in existing in vitro skin-sensitization tests. In the future, we expect a combination of original and modified h-CLAT to be applied in a newly developed in vitro test for evaluating skin sensitization.
最近，动物实验受到了关于动物福利的伦理、社会和政治方面日益增加的关注的影响。已经提出了几种用于评估皮肤致敏性的体外安全测试，例如人细胞系激活试验（h-CLAT）。然而，与其他测试类似，h-CLAT也产生了假阴性结果，包括在酸酐和水不溶性化学品的测试中。在先前的一项研究中，我们证明了邻苯二甲酸酐产生假阴性结果的原因是水性载体导致的水解，以及THP-1细胞释放白细胞介素-8，并且短时间暴露于液体石蜡（LP）分散介质可以减少酸酐的假阴性结果。在本研究中，我们通过应用这种暴露方法对h-CLAT进行了改进。我们发现改进后的h-CLAT是一种有前途的方法，可减少从酸酐和辛醇-水分配系数（LogK）大于3.5的化学品中获得的假阴性结果。基于本研究的结果，建议将原始的和改进后的h-CLAT结合使用以减少假阴性结果。值得注意的是，这种组合方法的灵敏度为9（总体化学品）或93%（LogK>2.0的化学品），准确度为88%（总体化学品）或81%（LogK>2.0的化学品）。我们发现这种组合方法是一种有前途的评估方案，可减少现有体外皮肤致敏性测试中出现的假阴性结果。在未来，我们期望原始的和改进后的h-CLAT组合应用于新开发的用于评估皮肤致敏性的体外测试中。
