Exposure to environmentally relevant concentrations of deltamethrin renders the Chinese rare minnow (Gobiocypris rarus) vulnerable to Pseudomonas fluorescens infection.
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| Abstract |
In this study, to assess the immunotoxicity of deltamethrin on fish, adult Chinese rare minnows (Gobiocypris rarus) were exposed to 0.1, 0.3, and 1 μg/L deltamethrin for 28 d. Many immunological parameters and histopathological alterations were determined. The results showed that lymphocyte number was markedly decreased at 0.3 and 1 μg/L treatments, whereas the neutrophil number was strongly increased at 1 μg/L treatments (p < 0.05). Furthermore, lysozyme (LYS), immunoglobulin M (IgM), and complement component 3 (C3) levels at 0.3 and 1 μg/L treatments were markedly reduced, whereas alkaline phosphatase (ALP) activity were marked increased at 1 μg/L treatments (p < 0.05). The transcripts of almost all TLR (Toll-like receptor) signaling pathway-related genes were up-regulated. Histological lesions in the livers, intestines, and gills were observed at all treatments. Then, all remaining fish from controls and deltamethrin-exposed groups were injected with Pseudomonas fluorescens (P. fluorescens) for 48 h. At 24 and 48 h post-injection with P. fluorescens (hpi), the lymphocyte numbers were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups, whereas LYS and C3 levels were strongly reduced at 0.3 and 1 μg/L deltamethrin-exposed groups (p < 0.05). Obvious reduces in IgM levels were also detected at 0.3 and 1 μg/L deltamethrin-exposed groups at 48 hpi (p < 0.05). The transcripts of almost all TLR signaling pathway-related genes were significantly down-regulated, whereas the levels of related microRNAs (miRNAs) were markedly increased at all deltamethrin-exposed groups at 24 and 48 hpi. Moreover, the bacterial load in the liver and the mortality of fish were significantly increased at 1 μg/L deltamethrin-exposed groups at 24 and 48 hpi (p < 0.05). Furthermore, obvious histological damage in the livers, intestines, and gills were observed at all deltamethrin-exposed fish at 48 hpi. Overall, our results demonstrated that environmentally relevant concentration deltamethrin suppressed immunity and rendered the fish vulnerable to P. fluorescens infection, subsequently inducing mortality.
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| Authors | Le Zhang, Xiangsheng Hong, Xu Zhao, Saihong Yan, Xufa Ma, Jinmiao Zha |
| Journal | The Science of the total environment (Sci Total Environ) Vol. 715 Pg. 136943 (May 01 2020) ISSN: 1879-1026 [Electronic] Netherlands |
| PMID | 32007896 (Publication Type: Journal Article) |
| Copyright | Copyright © 2020 Elsevier B.V. All rights reserved. |
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