Surfactin, an antibacterial peptide, produced by various Bacillus subtilis strains, have broad-spectrum antibacterial and immune-enhancing functions. In this study, we investigated the anti-inflammatory, antioxidant, and hepatoprotective effect of surfactin on zebrafish (Danio rerio) larvae following their exposure to copper sulfate (CuSO₄). The mature AB wild-type and a transgenic line of zebrafish larvae that expressed enhanced GFP (EGFP) named Tg (Lyz:EGFP) were exposed to 0, 20, 40, and 60 μg/mL surfactin after incubation with 3.2 μg/mL CuSO₄ for 2 h from 72 h postfertilization (hpf). Different endpoints, such as migration of GFP-labeled neutrophils, analysis of inflammatory cytokines and transaminases, markers of oxidation, expression of certain genes, and histological changes of liver, were studied to evaluate the function of surfactin. The protein expression levels of NF-κBp65, TNF-α, cyclooxygenase-2 (COX-2), and iNOS were determined in murine macrophage RAW 264.7 cells by western blotting. Our results show that surfactin reduced migration of neutrophils and relieved hepatic injury. In addition, surfactin reduced the index levels of inflammatory factors, oxidative stress response, and improved hepatic function. Surfactin also significantly inhibited the expression of IL-1β, IL-8, TNF-α, nitric oxide, NF-κBp65, COX-2, and iNOS, and increased the expression of IL-10. Thus, our results demonstrate that surfactin has anti-inflammatory, antioxidant, and hepatoprotective activities. Surfactin has potential as a novel inflammation and immune adjustment.

中文翻译：

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表面活性素对硫酸铜诱导的斑马鱼炎症、氧化应激和肝损伤的保护作用

Surfactin是一种抗菌肽，由各种枯草芽孢杆菌菌株产生，具有广谱抗菌和免疫增强功能。在这项研究中，我们研究了表面活性素对斑马鱼 ( Danio rerio ) 幼虫在接触硫酸铜 (CuSO ₄ ) 后的抗炎、抗氧化和保肝作用。成熟的 AB 野生型和表达增强型 GFP (EGFP) 的斑马鱼幼虫转基因品系，命名为 Tg (Lyz:EGFP)，在与 3.2 μg/mL CuSO孵育后暴露于 0、20、40 和 60 μg/mL 表面活性素₄受精后 72 小时 (hpf) 持续 2 小时。研究了不同的终点，如 GFP 标记的中性粒细胞的迁移、炎性细胞因子和转氨酶的分析、氧化标志物、某些基因的表达和肝脏的组织学变化，以评估表面活性素的功能。通过蛋白质印迹法在鼠巨噬细胞 RAW 264.7 细胞中测定 NF-κBp65、TNF-α、环氧合酶-2 (COX-2) 和 iNOS 的蛋白质表达水平。我们的结果表明，表面活性素减少了中性粒细胞的迁移并减轻了肝损伤。此外，surfactin 降低了炎症因子、氧化应激反应的指标水平，并改善了肝功能。Surfactin 还显着抑制 IL-1β、IL-8、TNF-α、一氧化氮、NF-κBp65、COX-2 和 iNOS 的表达，并增加 IL-10 的表达。因此，我们的研究结果表明，surfactin 具有抗炎、抗氧化和保肝活性。Surfactin 具有作为一种新型炎症和免疫调节的潜力。