Evaluation of the formation process and the biological effects of 3-nitrobenzanthrone, a strong mutagen newly identified from particulate matter in urban air.

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 14380259
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 環境影響評価(含放射線生物学)
• Research Institution: Sagami Women's University (2003-2004); National Institute of Public Health (2002)
• Principal Investigator: ADACHI Shuichi Sagami Women's University, Faculty of Liberal Arts, Associate Professor, 学芸学部, 助教授 (90129148)
• Co-Investigator(Kenkyū-buntansha): INAZU Kouji Tokyo Institute of Technology, Graduate School of Science and Engineering, Research Associate, 大学院・総合理工学研究科, 助手 (70272698)
• Project Period (FY): 2002 – 2004
• Keywords: Nitrobenzanthrone / Nitroarene / DNA adduct / Diesel / Lung tumor / Lung cancer / Mutagenicity / Air pollution

Research Abstract

Acute toxicity and carcinogenicity of 3-nitrobenzanthrone (3-NBA) were demonstrated by a series of animal experiments. All rats (F344/Nslc, female) had died within 6 months after the intratracheal administration of 3-NBA. These rats showed acute inflammation with metaplastic changes in the lung. Squamous cell carcinomas were induced dose dependently in both sex of rats (F344) after intratracheal administration. The highest level of DNA adducts was found in the lung, followed by the kidney and the liver. Up to 14 DNA adducts could be detected with four major ones varying between 50-90% of the total DNA adduct level. The maximum levels of DNA adducts were on average 240, 180 and 35 DNA adducts/10^8 normal nucleotides (NN) for lung, kidney and liver, respectively. There was also a significant difference (p <0.05) between lung/liver and kidney/liver but not between lung and kidney.
Although on-line reduction HPLC with chemiluminescence detection (R-HPLC-CLD) are much more sensitive to nitro arenes such as nitropyrenes up to by a factor of 1000 than conventional GC-MS system, the specific sensitivity would decrease when target NPAC have reactive functional groups or heteroatoms in the ring system, which are easy to be reductively decomposed, since formation of such reduced f products other than corresponding APAC results a decrease in the number of the APAC molecule detected by CLD. Moreover, if non APAC products are formed with unstable selectivity depending on the amount of NPAC, linear dose-response will be lost. 3-NBA is one of such NPAC with reactive carbonyl group. Thus feasibility of 3-NBA analysis by R-HPC-CLD was examined in sensitivity and accuracy (linearity of the response and variance). Unexpectedly, R-HPLC-CLD employed in this study exhibited quite high sensitivity to 3-NBA (20 fmol for detection limit and 80 fmol for quantification limit) comparable to 1,8-DNP, which is one of the most suitable NPAC for this method, and excellent linear response between 80-1500 fmol with RSD of 2.30/0. The conversion of 3-NBA to 3-ABA was estimated to be 880/0 under the reduction condition employed in this study. On the other hand, the sensitivity to 2-NTP was not so high among seven NPAC investigated (40 fmol for detection limit and 200 fmol for quantification limit) while linearity of the response and RSD were excellent.