RESUMO
The in vitro and in vivo immunoregulatory activity of a water-soluble sulfated fucan AL1-1 from the sea cucumber A. leucoprocta was elucidated. In vitro experiments showed that AL1-1 up-regulated immunostimulatory activities in RAW264.7 cells and that it could successfully promote ROS production and phagocytic activity, increase secretion levels of iNOS, and induce the production of considerable amounts of cytokines (TNF-α, IL-6, IL-1ß and IL-12). We found that toll-like receptor 4 (TLR4) was mainly involved in AL1-1 mediated macrophage activation. AL1-1's in vivo immunomodulatory activity on cyclophosphamide (CY)-treated mice was investigated and it was shown that it could strongly enhance Sig A levels, promote the total antioxidant capacity (T-AOC), and reduce malondialdehyde (MDA) level in the intestine. It could also increase activities of superoxidase dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). These results demonstrate that AL1-1 has a significant effect on enhancing in vivo and in vitro immune response.