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Liu H, Cheng L, Hu Y, Chen D, Wang X, Zhang X, Li Z, Wu Z. Hepatotoxicity of oral exposure to 2-methyl-4-nitroaniline: toxicity prediction and in vivo evaluation. Toxicol Lett 2024; 399:1-8. [PMID: 38969027 DOI: 10.1016/j.toxlet.2024.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 06/18/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
2-Methyl-4-nitroaniline (MNA), an intermediate in the synthesis of azo dyes, is widely distributed in various environmental media and organisms. Although there is speculation regarding MNA's potential to be hepatotoxic, the underlying mechanisms of its hepatotoxicity and its definitive diagnostic process remain largely unexplored. In this research. In the present study, we initially predicted the toxicity and possible toxic effect pathways of MNA using ProTox-II, and found that MNA binds to the PPARγ receptor (binding energy -6.118 kcal/mol) with a potential PPARγ agonist effect. Subsequently, in vivo exposure evaluation was conducted on Wistar rats to assess the impact of MNA after a 90-day exposure period, by detecting serum biochemical indexes, hematological indexes, urinary indexes, inflammatory factors, liver histopathological observations and liver tissue PPARγ mRNA expression. The results showed that MNA causes liver function abnormalities, liver histopathological changes and inflammatory response, along with a pronounced increase in PPARγ mRNA levels. This study suggests that the hepatotoxic mechanism of MNA may be related to its possible upregulation of PPARγ expression, increased liver dysfunction and inflammatory responses. Based on these results, the benchmark dose lower limit (BMDL) of 1.503 mg/kg for male Wistar rats was also established, providing a vital benchmark for determining the safety threshold of MNA. Our data highlight the hepatotoxic mechanism of MNA and contribute to a better understanding of its potential etiological diagnosis.
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Affiliation(s)
- Haiwei Liu
- General Surgery Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China
| | - Le Cheng
- Oncology Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China.
| | - Yili Hu
- Oncology Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China
| | - Diandian Chen
- Oncology Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China
| | - Xiaobo Wang
- Oncology Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China
| | - Xianlin Zhang
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, China Three Gorges University, Yichang 443002, PR China
| | - Zheng Li
- Oncology Department, Affiliated Renhe Hospital of China Three Gorges University, Yichang 443002, PR China
| | - Zhe Wu
- Research Center of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, PR China.
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Frawley RP, Witt KL, Cunny H, Germolec DR, Jackson-Humbles D, Malarkey D, Shockley KR, Stout M, Travlos G, Buccellato M, Fallacara D, Harris S, Kissling GE, Manheng W, Surh II, White K, Auerbach SS. Evaluation of 2-methoxy-4-nitroaniline (MNA) in hypersensitivity, 14-day subacute, reproductive, and genotoxicity studies. Toxicology 2020; 441:152474. [PMID: 32380031 DOI: 10.1016/j.tox.2020.152474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 10/24/2022]
Abstract
2-Methoxy-4-nitroaniline (MNA), an intermediate in the synthesis of azo dyes used in textiles and paints, is structurally similar to carcinogenic anilines. Human exposure occurs primarily in the occupational setting through handling of dye dust, and through use and disposal of MNA-containing products. MNA has been reported to induce contact hypersensitivity in a human, myocardial necrosis in rats, and bacterial mutagenicity. This study assessed the subacute toxicity, genotoxicity, contact hypersensitivity, and reproductive toxicity of MNA in rodents in an effort to more fully characterize its toxicological profile. B6C3F1/N mice were exposed to 0, 650, 1250, 2500, 5000, or 10,000 ppm MNA by dosed feed for 14-days to evaluate subacute toxicity and histopathological endpoints. In female mice, decreased body weight (13.5 %) and absolute kidney weight (14.8 %), compared to control, were observed at 10,000 ppm MNA; increased relative liver weight (10-12 %), compared to control, occurred at 5,000-10,000 ppm MNA. In male mice, absolute (15 %) and relative liver weights (9-13 %) were increased at 2,500-5,000 ppm and 1250-10,000 ppm MNA, compared to control, respectively. In both sexes of mice, minimal elevations of hemosiderin pigmentation (a breakdown product of erythrocytes), relative to control, were observed in the liver (10,000 ppm); minimal to moderate elevations of hemosiderin pigmentation (5,000-10,000 ppm) and minimal increases in hematopoietic cell proliferation occurred in the spleen (≥ 1250 ppm). In a reproductive toxicity study, timed-mated female Harlan Sprague Dawley rats were exposed to 0-10,000 ppm MNA by dosed feed from gestation day 6 through postnatal day (PND) 21. Decreases in mean litter weights were observed at 5000 ppm MNA, compared to control, beginning at PND1. To evaluate potential contact hypersensitivity, MNA (2.5-50 %, in dimethylformamide) was applied to the dorsa of both ears of female Balb/c mice once daily for three days. The increase observed in lymph node cell proliferation (10-50 % increase in thymidine uptake compared to control) did not reproducibly achieve the Sensitization Index (SI) 3 level, and there was no ear swelling evident following sensitization with 10-50 % MNA and challenge with 25 % MNA in the mouse ear swelling test. In bacterial mutagenicity assays, MNA (250-1000 μg/plate) induced significant increases, compared to control, in mutant colonies with and without metabolic activation enzymes in Salmonella typhimurium strains TA100 and TA98. These data indicate that MNA is genotoxic, and may induce erythrocyte damage and reactive phagocytosis by macrophages in the liver and spleen.
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Affiliation(s)
- Rachel P Frawley
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA.
| | - Kristine L Witt
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Helen Cunny
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Dori R Germolec
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Daven Jackson-Humbles
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - David Malarkey
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Keith R Shockley
- Division of Intramural Research, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Matthew Stout
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Greg Travlos
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | | | | | - Shawn Harris
- Social & Scientific Systems, Inc., 4505 Emperor Blvd, Suite 400, Durham, NC, 27703, USA
| | - Grace E Kissling
- Division of Intramural Research, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Wimolnut Manheng
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, VCU Medical Center, 1201 E Marchall ST #4-100, Richmond, VA, 23298, USA
| | - Irene Inok Surh
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
| | - Kimber White
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, VCU Medical Center, 1201 E Marchall ST #4-100, Richmond, VA, 23298, USA
| | - Scott S Auerbach
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC, 27709, USA
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