龙须菜多糖硫酸化对免疫活性的影响

分别采用改良的氯磺酸- 吡啶法和HCl- 甲醇法对龙须菜多糖进行硫酸化修饰与脱硫处理，探讨不同硫酸基含量的天然多糖、硫酸化多糖和脱硫多糖对由环磷酰胺引起的免疫力低下小鼠免疫功能的影响。结果表明：与模型组比较，天然多糖对提高小鼠的脾脏指数(P ＜ 0.05)、巨噬细胞的吞噬活性(P ＜ 0.05)、脾细胞增殖转化能力(P ＜ 0.05)、NK 细胞杀伤活性(P ＜ 0.01)等作用最强，其次是硫酸化多糖，而脱硫多糖作用最弱；这3 种多糖都能显著促进免疫抑制小鼠的溶血素和溶血空斑的形成(P ＜ 0.01)，其中天然多糖和硫酸化多糖优于脱硫多糖。显示龙须菜多糖能显著提高免疫力低下小鼠的免疫功能，但多糖中硫酸基含量与免疫作用非线性关系，增加或脱除天然多糖硫酸基其免疫活性均下降，尤其是脱除硫酸基后免疫活性显著降低。

Immunoregulatory Effects of Sulfurized,Desulfurized and Native Gracilaria lemaneiformis Polysaccharides in Immunosuppressive Mice

Improved chlorosulfonic acid/pyridine and HCl/methyl alcohol methods were used for sulfurizing and desulfurizing native Gracilaria lemaneiformis polysaccharides, respectively. The immunoregulatory effects of sulfurized, desulfurized and native Gracilaria lemaneiformis polysaccharides in mice with low immunity induced by cyclophosphamide were investigated. Compared with the model group, native Gracilaria lemaneiformis polysaccharides were the most effective in improving spleen index (P＜0.05), phagocytic activity of macrophages (P＜0.05), proliferation and transformation of spleen cells (P＜0.05) and NK cell killing activity (P＜0.01), followed by sulfurized and desulfurized ones. All three polysaccharides could significantly improve the formation of hemolysin and hemolytic plaque in immunosuppressive mice (P ＜ 0.01), native and sulfurized Gracilaria lemaneiformis polysaccharides were superior to desulfurized ones. Based on these results, it can be concluded that Gracilaria lemaneiformis polysaccharides significantly increase the immune function in immunocompromised mice, that sulfate content in Gracilaria lemaneiformis polysaccharides is nonlinearly related to their immunoregulatory effect in immunocompromised mice, and that both sulfurization and desulfurization decrease the immunoregulatory effect of native Gracilaria lemaneiformis polysaccharides, especially desulfurization resulted in a significant decrease.