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Do VQ, Seo YS, Park JM, Yu J, Duong MTH, Nakai J, Kim SK, Ahn HC, Lee MY. A mixture of chloromethylisothiazolinone and methylisothiazolinone impairs rat vascular smooth muscle by depleting thiols and thereby elevating cytosolic Zn 2+ and generating reactive oxygen species. Arch Toxicol 2020; 95:541-556. [PMID: 33074372 DOI: 10.1007/s00204-020-02930-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 10/08/2020] [Indexed: 12/26/2022]
Abstract
Chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) are biocidal preservatives and the active ingredients in Kathon CG, which contains ca. 1.5% mixture of CMIT and MIT at a ratio of 3:1 (CMIT/MIT). CMIT/MIT was misused as humidifier disinfectant products, which caused serious health problems in Korea. Here, the vascular effects of CMIT/MIT were investigated to evaluate claims of putative cardiovascular toxicity observed in humidifier disinfectant users. CMIT/MIT did not affect the basal tension of the rat thoracic aorta up to 2.5 μg/mL in myograph experiments. Instead, pretreatment with CMIT/MIT impaired phenylephrine- or 5-hydroxytryptamine-induced vasoconstriction in a range of 0.5-2.5 μg/mL, which was largely irreversible and not recovered by washing out the CMIT/MIT. Similarly, the application of CMIT/MIT to pre-contracted aorta caused a gradual loss of tension. In primary cultured vascular smooth muscle cells (VSMCs), CMIT/MIT caused thiol depletion, which in turn led to cytosolic Zn2+ elevation and reactive oxygen species (ROS) formation. CMIT/MIT-induced shrinkage, detachment, and lysis of VSMCs depending on the concentration and the treatment time. All events induced by CMIT/MIT were prevented by a thiol donor N-acetylcysteine (NAC). Cytolysis could be inhibited by a Zn2+ chelator TPEN and a superoxide scavenger TEMPOL, whereas they did not affect shrinkage and detachment. In accordance with these results, CMIT/MIT-exposed aortas exhibited dissociation and collapse of tissue in histology analysis. Taken together, CMIT/MIT causes functional impairment and tissue damage to blood vessels by depleting thiol and thereby elevating cytosolic Zn2+ and generating ROS. Therefore, exposure to CMIT/MIT in consumer products may be a risk factor for cardiovascular disorders.
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Affiliation(s)
- Van Quan Do
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Yoon-Seok Seo
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Jung-Min Park
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Jieun Yu
- College of Pharmacy, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Men Thi Hoai Duong
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Junichi Nakai
- Graduate School of Dentistry, Tohoku University, Miyagi, 980-8575, Japan
| | - Sang-Kyum Kim
- College of Pharmacy, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Hee-Chul Ahn
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea
| | - Moo-Yeol Lee
- College of Pharmacy, Integrated Research Institute for Drug Development, and BK21 FOUR team, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, 10326, Republic of Korea.
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