Effect of fucoidan and fraction isolated from laminaria japonicaon immunity of broiler macrophages under oxidation stress condition

chinois. 【目的】在氧化应激条件下，研究海带岩藻聚糖及其级分对肉鸡巨噬细胞免疫功能的影响，初步探讨海带岩藻聚糖及其级分的免疫调节功能与抗氧化作用的关系。【方法】以叔丁基过氧化氢（tBOOH）为活性氧诱导剂，加入肉鸡腹腔巨噬细胞培养液中，测定细胞培养液中抗氧化酶的变化，巨噬细胞分泌一氧化氮（NO）、诱导型一氧化氮合成酶（iNOS）、以及细胞因子IL-1和TFN-α等免疫指标的变化。【结果】用tBOOH处理后的巨噬细胞，细胞存活率显著下降（P〈0.05），乳酸脱氢酶（LDH）和丙二醛（MDA）显著升高（P〈0.05），SOD和GSH-Px酶活性显著降低（P〈0.05）。巨噬细胞的吞噬活性显著降低（P〈0.05），NO、iNOS和呼吸爆发显著降低（P〈0.05），细胞因子IL-1分泌量显著下降（P〈0.05），表明细胞出现明显的氧化损伤。在培养液中加入海带岩藻聚糖及其级分，能够缓解细胞的氧化应激，使得细胞存活率上升，LDH和MDA降低，SOD和GSH-Px升高，免疫指标均有不同程度的恢复。【结论】海带岩藻聚糖及其级分具有抗氧化活性，不同级分的抗氧化活性存在差异，其中级分Ⅲ、级分Ⅳ的作用较强。海带岩藻聚糖对巨噬细胞的免疫促进作用与其抗氧化活性有关。

anglais. [Objective] The immunomodulatory activities of a fucoidan （FLJ） and its fraction, purified from the Laminaria japonica, were investigated in vitro under oxidation stress in broiler macrophages. [Method] After the broiler macrophages were cultured with FLJ and its fraction for 24 h, the tBOOH was added to the culture as oxygen reagent. The activities of superoxide dismutase （SOD）, glutathione peroxidase （GSH-Px） and induced nitric oxide synthase （iNOS） were detected. The content of lactate dehydrogenase （LDH）, malonic dialdehyde （MDA）, NO, IL-1 and TNF-α were measured. Production of reactive oxygen species （ROS） in macrophages was measured by luminal dependent chemiluminescence. [Result] The elevated MDA and LDH, decreased cell vialibility, increased SOD and GSH-Px levels indicated that adding tBOOH in culture caused the oxidation stress in broiler macrophages. The decrease of phagocytic activity, NO, iNOS, IL-land respiratory burst capacity indicated that the immune function of broiler macrophages were influenced by tBOOH. When the FLJ and its fraction were present in culture, the oxidation stress were eliminated. The cell vialibility, SOD and GSH-Px were significantly increased （P〈0.05）, LDH and MDA were significantly decreased （P〈0.05）. The immune function of macrophages was enhanced. [Conclusion] The different fractions of FLJ have different antioxidant activities. Fraction Ⅲ and fraction Ⅳ have the most effective antioxidant activities. These data suggest that the FLJ and its fractions have antioxidant activities, and the antioxidant activities of FLJ and its fractions are related to their immunomodulatory activities.