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Abstract：
Ascophyllan HS is a commercially available preparation of the edible brown alga Ascophyllum nodosum containing ascophyllan, a sulfated polysaccharide with diverse beneficial biological activities. In this study, the effects of ascophyllan HS were evaluated in a severe intranasal Streptococcus pneumoniae infection mouse model. The control untreated mice started to die on day 7 and 80% had died by day 14 post-infection. Continuous oral administration of ascophyllan HS before and after bacterial infection resulted in a remarkable increase in survival rate, with 90% of the low (167 mg/kg body weight/day) and 100% of the high (500 mg/kg body weight/day) dose ascophyllan HS-treated mice surviving at day 14 post-infection. Histopathological observation of the lungs of the infected mice revealed the induction of typical pneumonia features in the alveolar spaces of the untreated control mice, such as extensive infiltration of inflammatory cells, edema, and fibrin deposition. In contrast, notable levels of lung injuries or alterations were not observed in the ascophyllan HS-treated mice, and only a minor lesion was observed in one mouse. Furthermore, bacterial burdens in the lungs were significantly reduced in the ascophyllan HS-treated mice as compared to the control mice at day 4 post-infection. Significantly higher levels of IL-12 were detected in the serum of ascophyllan HS-treated mice than that of control mice measured at the end of the infection experiment (day 14). These results suggest that orally administered ascophyllan HS exerts a therapeutic effect on S. pneumoniae infection by activating the host defense systems. This is the first report of the therapeutic effect of an orally administered seaweed polysaccharide preparation on S. pneumoniae infection. Our findings suggest that ascophyllan HS has the potential to be developed as nutraceuticals and pharmaceuticals applicable for humans as well as a safe and promising therapeutic agent against S. pneumoniae infection.
摘要：
AscophylanHS是可食用的棕色藻类Ascophylumnodosum的市售制剂，一种具有多种有益生物活性的硫酸多糖。在这项研究中,在严重的鼻内肺炎链球菌感染小鼠模型中评估了天冬多糖HS的作用.未处理的对照小鼠在第7天开始死亡,并且80%在感染后第14天死亡。在细菌感染之前和之后连续口服ascophyllanHS导致存活率显着提高，感染后第14天，90％的低剂量（167mg/kg体重/天）和100％的高剂量（500mg/kg体重/天）的天冬草HS处理小鼠存活。对感染小鼠肺部的组织病理学观察显示，未经治疗的对照小鼠的肺泡腔中诱导了典型的肺炎特征，如炎性细胞的广泛浸润，水肿,和纤维蛋白沉积.相比之下,在接受ascophylillanHS治疗的小鼠中未观察到明显的肺损伤或改变，在一只小鼠中只观察到轻微的损伤。此外，与感染后第4天的对照小鼠相比，在接受ascophylillanHS治疗的小鼠中，肺中的细菌负荷显着降低。与在感染实验结束时(第14天)测量的对照小鼠相比,在用天花树HS处理的小鼠的血清中检测到显著更高水平的IL-12。这些结果表明,口服施用的天冬多糖HS通过激活宿主防御系统对肺炎链球菌感染发挥治疗作用。这是口服施用的海藻多糖制剂对肺炎链球菌感染的治疗效果的首次报道。我们的发现表明，蛇床子HS有可能被开发为适用于人类的营养品和药物，以及针对肺炎链球菌感染的安全和有前途的治疗剂。
