Article ID: JOSH-2019-0008-TA
3,3’-dichloro-4,4’-diaminodiphenylmethane (MOCA), an industrial chemical used as a curing agent for polyurethane pre-polymers, is known as a carcinogen that may cause occupational bladder cancer. Generation of DNA damage is a crucial first step in carcinogenesis, and it is clear from the previous studies that MOCA is genotoxic. On the other hand, it is still unknown whether MOCA produces a DNA double strand break, the most severe DNA damage closely related to carcinogenesis. In addition, there are no studies comparing genotoxicity between MOCA and the substances having similar chemical structures and using same application as MOCA. In this study, in order to grasp the hazard of chemical substances accurately, we carried out comparison of DNA damage properties among MOCA, 4,4’-diaminodiphenylmethane, 4,4’-diamino-3,3’-dimethyldiphenylmethane, and 4,4’-dihydroxydiphenylmethane using phosphorylated histone H2AX, having attracted attention in recent years as a biomarker of DNA doublestrand breaks. We found that all four tested substances induced γH2AX, and the induction was particularly strong in MOCA and 4,4’-dihydroxydiphenylmethane. The findings of this study are considered to provide important information for risk assessment of tested substances.
