Embryonic exposure to 4‐methylimidazole leads to zebrafish myofibril misalignment

• Published in: Environmental toxicology 2018-12, Vol.33 (12), p.1321-1328
• Main Authors: Tsai, Jen‐Ning, Sun, Chiao‐Yin, Ding, Yu‐Ju, Wang, Yun‐Hsin, Lo, Kang‐Chieh, Wen, Chi‐Chung, Lin, Jia‐Wei, Chang, Chiung‐Fang, Hsu, Li‐Sung, Chen, Hui‐Min, Fong, Tsorng‐Harn, Chen, Yau‐Hung
• Format: Article
• Language: English
• Subjects: 4‐methylimidazole; Alignment; Animal embryos; Animals; Beverages; Caramel; Chemical compounds; Colour; Danio rerio; Duration; Electron microscopy; Embryo, Nonmammalian - drug effects; Embryogenesis; Embryonic Development - drug effects; Embryonic growth stage; Embryos; Exposure; Filaments; Freshwater fishes; Gene expression; Imidazole; Imidazoles - toxicity; Immunofluorescence; Microscopy; Misalignment; Muscle Development - drug effects; Muscles; MyoD protein; Myofibrils - drug effects; Myofibrils - physiology; Myogenesis; Myogenin; Organic chemicals; Organic chemistry; Organizations; Phenotypes; Raw materials; Sauces; Soft drinks; Soybeans; Teratogenicity; Ultrastructure; Zebrafish; Zebrafish - embryology; Zebrafish Proteins - metabolism
• ISSN: 1520-4081; 1522-7278
• DOI: 10.1002/tox.22640

4‐methylimidazole (4‐MI) is an imidazole‐derived organic chemical compound that can be used as a raw material in the manufacture of diverse chemicals and has been identified as an ingredient of caramel color in soybean sauce, beers, and other soft drinks. The aim of the present study was to investigate the teratogenic effects of 4‐MI during zebrafish embryogenesis. Zebrafish embryos were treated with different dosages of 4‐MI (0‐120 mM) for different exposure durations (12‐60 hours). The percentages of embryos with malformed phenotypes increased as the exposure dosages and duration time of 4‐MI increased. We also used immunofluorescence and transmission microscopy to evaluate the subtle changes in the myofibril alignment and ultrastructure of muscle organization. Our data showed that 4‐MI treatment disturbs muscle fiber alignment. Electron microscopy data indicated that Z‐lines were undetectable in the 4‐MI‐treated embryos. Although the thick and thin filaments were visible, they were all disorganized. In addition, zebrafish embryos treated by 4‐MI exhibited aberrant expression of 2 muscle‐specific genes, myod and myogenin. Taken together, we concluded that early exposure to 4‐MI affects zebrafish myogenesis, especially in myofibril alignment.