Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish
The combined pollution of cadmium (Cd) and enrofloxacin (ENR) in aquatic environments represents a critical issue in environmental toxicology. Using zebrafish as model organisms, we systematically investigated the combined toxicity of Cd and ENR through both acute (96-h) and chronic (20-d) exposure...
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MDPI AG
2025-05-01
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| author | Lingfei Ren Yu He Chao Hou Chaoxuan Liao Miao Chen |
| author_facet | Lingfei Ren Yu He Chao Hou Chaoxuan Liao Miao Chen |
| author_sort | Lingfei Ren |
| collection | DOAJ |
| description | The combined pollution of cadmium (Cd) and enrofloxacin (ENR) in aquatic environments represents a critical issue in environmental toxicology. Using zebrafish as model organisms, we systematically investigated the combined toxicity of Cd and ENR through both acute (96-h) and chronic (20-d) exposure experiments. Our results demonstrated significant synergistic effects: co-exposure reduced the 96-h LC50 values from 89.12 mg/L (Cd alone) and 190.11 mg/L (ENR alone) to 46.35 mg/L and 99.39 mg/L, respectively (combined effect index = 0.96). Chronic exposure revealed that ENR enhanced Cd accumulation in the liver, intestine, and muscle tissues by 1.11–2.33-fold compared to single Cd exposure. Oxidative stress markers showed dynamic temporal changes, with superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities initially increasing by 1.34–7.06-fold, 0.98–3.28-fold, and 1.53–3.65-fold at 8 d, respectively, followed by 9.9–48.98% reductions after 20 d of exposure. Malondialdehyde (MDA) levels progressively accumulated, reaching up to 4.06-fold higher than controls. Notably, co-exposure elevated oxidative stress by 11.24–34.48% relative to single exposures. The 16S rDNA sequencing analysis indicated that Cd exposure significantly reduced the α-diversity of zebrafish gut microbiota (57–63% decrease in Shannon index), characterized by a 16–20% reduction in beneficial <i>Cetobacterium</i> and a 44–114% increase in pathogenic <i>Aeromonas</i> abundance. The combined exposure further exacerbated these gut microbiota dysbiosis patterns. These findings provide crucial evidence for ecological risk assessment, suggesting that current environmental standards based on single-pollutant evaluations may substantially underestimate the actual risks of heavy metal-antibiotic co-contamination in aquatic ecosystems. |
| format | Article |
| id | doaj-art-c7691642f0b64e25b6acb5ce046571d5 |
| institution | Kabale University |
| issn | 2305-6304 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | MDPI AG |
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| series | Toxics |
| spelling | doaj-art-c7691642f0b64e25b6acb5ce046571d52025-08-20T03:47:57ZengMDPI AGToxics2305-63042025-05-0113537810.3390/toxics13050378Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on ZebrafishLingfei Ren0Yu He1Chao Hou2Chaoxuan Liao3Miao Chen4College of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, ChinaGuizhou Academy of Testing and Analysis, Guiyang 550014, ChinaCollege of Ecological Environment Engineering, Guizhou University for Nationalities, Guiyang 550025, ChinaGuizhou Academy of Testing and Analysis, Guiyang 550014, ChinaCollege of Resources and Environmental Engineering, Guizhou University, Guiyang 550025, ChinaThe combined pollution of cadmium (Cd) and enrofloxacin (ENR) in aquatic environments represents a critical issue in environmental toxicology. Using zebrafish as model organisms, we systematically investigated the combined toxicity of Cd and ENR through both acute (96-h) and chronic (20-d) exposure experiments. Our results demonstrated significant synergistic effects: co-exposure reduced the 96-h LC50 values from 89.12 mg/L (Cd alone) and 190.11 mg/L (ENR alone) to 46.35 mg/L and 99.39 mg/L, respectively (combined effect index = 0.96). Chronic exposure revealed that ENR enhanced Cd accumulation in the liver, intestine, and muscle tissues by 1.11–2.33-fold compared to single Cd exposure. Oxidative stress markers showed dynamic temporal changes, with superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities initially increasing by 1.34–7.06-fold, 0.98–3.28-fold, and 1.53–3.65-fold at 8 d, respectively, followed by 9.9–48.98% reductions after 20 d of exposure. Malondialdehyde (MDA) levels progressively accumulated, reaching up to 4.06-fold higher than controls. Notably, co-exposure elevated oxidative stress by 11.24–34.48% relative to single exposures. The 16S rDNA sequencing analysis indicated that Cd exposure significantly reduced the α-diversity of zebrafish gut microbiota (57–63% decrease in Shannon index), characterized by a 16–20% reduction in beneficial <i>Cetobacterium</i> and a 44–114% increase in pathogenic <i>Aeromonas</i> abundance. The combined exposure further exacerbated these gut microbiota dysbiosis patterns. These findings provide crucial evidence for ecological risk assessment, suggesting that current environmental standards based on single-pollutant evaluations may substantially underestimate the actual risks of heavy metal-antibiotic co-contamination in aquatic ecosystems.https://www.mdpi.com/2305-6304/13/5/378antibioticsheavy metalscombined impactantioxidant enzymesintestinal flora |
| spellingShingle | Lingfei Ren Yu He Chao Hou Chaoxuan Liao Miao Chen Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish Toxics antibiotics heavy metals combined impact antioxidant enzymes intestinal flora |
| title | Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish |
| title_full | Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish |
| title_fullStr | Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish |
| title_full_unstemmed | Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish |
| title_short | Toxicological Effects of Combined Exposure of Cadmium and Enrofloxacin on Zebrafish |
| title_sort | toxicological effects of combined exposure of cadmium and enrofloxacin on zebrafish |
| topic | antibiotics heavy metals combined impact antioxidant enzymes intestinal flora |
| url | https://www.mdpi.com/2305-6304/13/5/378 |
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