Department of Marine Biotechnology, Gangneung-Wonju National University, Gangneung, 25457, South Korea.
Department of Marine Food Science and Technology, Gangneung-Wonju National University, Gangneung, 25457, South Korea.
Fish Shellfish Immunol. 2021 May;112:125-134. doi: 10.1016/j.fsi.2021.03.001. Epub 2021 Mar 15.
Sulfated polysaccharides (SPs) derived from Codium fragile (sponge seaweed) can regulate cytokine expression in mammalian macrophages, NK cell lines and olive flounder head kidney primary cells in vitro. In this study, we found that SPs from C. fragile exhibited anti-bacterial activities against fish pathogenic bacteria including Streptococcus parauberis, Lactococcus garvieae, Aeromonas salmonicida and Edwardsiella tarda at a minimum inhibitory concentration of 2 mg/mL, but not against S. iniae or Vibrio anguillarum. Immunostimulatory effects of SPs from C. fragile on rockfish (Sebastes schlegelii) were evaluated by analyzing mRNA expression levels of inflammatory cytokines (interleukin (IL)-1β, IL-8, IL-6 and tumor necrosis factor (TNF)-α) and anti-inflammatory cytokines (IL-10) both in vitro and in vivo. Results revealed that expression levels of all genes tested were upregulated in rockfish head kidney and spleen cells by SPs from C. fragile in a dose/time-dependent manner in vitro. By contrast, expression levels of these genes were significantly (p < 0.05) downregulated in the head kidney and spleen of rockfish in vivo at 1 and 3 days post intraperitoneal injection of SPs from C. fragile. In the liver, these genes were downregulated on day 1, but upregulated on day 3. Treatment with SPs downregulated the expression of these genes in spleen, but upregulated IL-10 gene expression in the intestine and liver. Meanwhile, when fish were fed with crude SPs for 4 weeks and challenged with E. tarda, infected fish started to die starting from 2 days after immune challenge. The cumulative mortality of the 0.1% group was significantly lower (p < 0.05) than that of the control group without feeding with SPs. Expression levels of IL-1β and IL-6 genes were significantly (p < 0.05) upregulated in head kidney of the 0.5% group on day 1 while IL-1β gene expression was downregulated on day 3 in the liver. These results indicate that SPs from C. fragile can regulate the immune gene expression in rockfish and that a diet containing 0.1% crude SPs can reduce the mortality of rockfish caused by E. tarda infection.
从脆江蓠（海绵海藻）中提取的硫酸多糖（SPs）可以调节哺乳动物巨噬细胞、NK 细胞系和橄榄石斑鱼头肾原代细胞中的细胞因子表达。在这项研究中，我们发现脆江蓠 SPs 在最低抑制浓度 2mg/mL 时对包括鳗弧菌、迟缓爱德华氏菌、鳗弧菌和迟缓爱德华氏菌在内的鱼类病原菌具有抗菌活性，但对迟缓爱德华氏菌或鳗弧菌没有抗菌活性。通过分析炎性细胞因子（白细胞介素 (IL)-1β、IL-8、IL-6 和肿瘤坏死因子 (TNF)-α）和抗炎细胞因子（IL-10）在体外和体内的 mRNA 表达水平，评估了脆江蓠 SPs 对青石斑鱼（Sebastes schlegelii）的免疫刺激作用。结果表明，体外脆江蓠 SPs 以剂量/时间依赖性方式上调青石斑鱼头肾和脾脏细胞中所有测试基因的表达。相比之下，在脆江蓠 SPs 腹腔注射后 1 和 3 天，青石斑鱼头肾和脾脏中这些基因的表达水平显著（p<0.05）下调。在肝脏中，这些基因在第 1 天下调，但在第 3 天上调。SPs 处理下调了脾脏中这些基因的表达，但上调了肠道和肝脏中 IL-10 基因的表达。同时，当鱼连续 4 周摄食粗 SPs 并受到迟缓爱德华氏菌攻击时，感染鱼从免疫攻击后 2 天开始死亡。0.1%组的累积死亡率明显低于（p<0.05）未摄食 SPs 的对照组。在 0.5%组中，第 1 天头肾中 IL-1β 和 IL-6 基因的表达水平显著（p<0.05）上调，而第 3 天肝脏中 IL-1β 基因的表达下调。这些结果表明，脆江蓠 SPs 可以调节青石斑鱼的免疫基因表达，并且含有 0.1%粗 SPs 的饮食可以降低迟缓爱德华氏菌感染引起的青石斑鱼死亡率。
