Elucidating mechanisms of immunotoxicity by benzotriazole ultraviolet stabilizers in zebrafish (Danio rerio): Implication of the AHR-IL17/IL22 immune pathway

Date of publication 8 June 2020

Authors Li, Zhitong; Liang, Xuefang; Liu, Wang; Zhao, Yaqian; Yang, Huiting; Li, Wenjing; Adamovsky, Ondrej; Martyniuk, Christopher J.

Sources Environmental pollution (Barking, Essex : 1987) : 262, 114291.

DOILink https://doi.org/10.1016/j.envpol.2020.114291


Benzotriazole ultraviolet stabilizers (BUVSs) are widely used additives in industrial materials and personal care products that protect products from ultraviolet damage. Due to their high production volume and potential to bioaccumulate, BUVSs are an environmental pollutant of concern. In this study, juvenile zebrafish (Danio rerio) were exposed to 4 BUVSs (UV-234, UV-326, UV-329, and UV-P) at 10 and 100 μg/L for 28 d. BUVSs induced hepatic vacuolization and nuclei pyknosis in the liver following 100 μg/L UV-234 and UV-329 exposure. Transcriptomic analysis in the liver uncovered pathways related to inflammation that were affected by BUVSs. Based upon these data, we measured the expression levels of 9 genes involved in AHR-IL17/IL22 pathway in zebrafish larvae exposed to each BUVSs at one dose of either 10 or 100 μg/L for 6 days in a second set experiment. Transcript levels of interleukins il17a and il22 were decreased, while il6 mRNA was increased with exposure to UV-234, UV-329, and UV-P. No change to targeted transcripts was observed with UV-326 treatments. Moreover, cyp1a1 and ahr2 levels were increased in larvae treated with 100 μg/L UV-329 or UV-P. Consistent with expression data, protein abundance of IL22 was decreased by 29% with exposure to 100 μg/L UV-P. Taken together, these results demonstrate that exposure to different benzotriazole congeners may be associated with immunotoxicity in zebrafish through the AHR-IL17/IL22 pathway, and this may be associated with hepatic damage with prolonged exposures. This study provides new insight into unique pathways perturbed by specific BUVSs congeners.

TSC Opinion

L’un des problèmes de la pollution plastique est la diffusion de leurs additifs dans l’environnement. A la conception des matériaux, la diffusion des additifs est très lente, ce qui permet un usage de molécules parfois toxiques pour l’environnement et/ou pour l’homme. En effet, la faible diffusion rend les quantités d’additifs disponibles en surface du matériau très faibles et donc peu toxiques. Lorsque l’objet en plastique est dégradé dans l’environnement, il est fragmenté et la diffusion des additifs augmente proportionnellement à la surface de contact. Leur toxicité augmente fortement, en particulier si les microparticules de plastiques sont ingérées par des organismes vivants. Cette étude présente le cas des benzotriazoles, additifs anti-UV, et de leurs effets sur les poissons zèbres. Les résultats montrent une atteinte significative du foie des poissons pour des expositions prolongées.

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