壳寡糖激活巨噬细胞的机制

目的：探讨巨噬细胞结合、内吞壳寡糖以及壳寡糖激活巨噬细胞的机制。方法：利用荧光物质2-氨基吖啶酮标记壳寡糖，在激光共聚焦显微镜下观察巨噬细胞内吞壳寡糖的过程，流式细胞仪分析细胞的荧光强度，通过竞争性抑制实验及钙离子、胰蛋白酶、秋水仙碱对内吞的影响来确定巨噬细胞内吞壳寡糖的机制。通过RT—PCR方法检测TNF—α来反映结合及内吞过程对壳寡糖刺激巨噬细胞的影响。结果：巨噬细胞可结合内吞壳寡糖。内吞易受温度影响，37C较迅速（〈2min），4C只能结合不能内吞。EDTA可抑制巨噬细胞内吞壳寡糖；经胰蛋白酶预处理的巨噬细胞摄取壳寡糖的能力大大降低，终止胰蛋白酶后巨噬细胞摄取壳寡糖的能力得到恢复。秋水仙碱预处理可明显抑制巨噬细胞摄取壳寡糖，并呈剂量依赖性。0．1mol／L甘露糖可抑制壳寡糖对巨噬细胞的刺激作用。结论：甘露糖受体介导的吞饮是巨噬细胞内吞壳寡糖的一条重要途径，甘露糖受体在壳寡糖激活巨噬细胞中起重要作用。

Mechanism of oligochitosan-induced macrophage activation

OBJECTIVE: To study the mechanism of oligochitosan-induced macrophage activation. METHODS: Oligochitosan was chemically modified with fluorophore 2-aminoacridone (2-AMAC). The cellular events of 2-AMAC-oligochitosan-macrophage interaction were analyzed with confocal laser microscopy and the fluorescence intensity of cells was analyzed by BD LSR flow cytometer. The mechanism of oligochitosan uptake by macrophages was studied by competitive inhibition test and the effect of calcium, trypsin and colchicine on oligochitosan recognition and internalization were also determined. RT-PCR was performed to investigate the level of TNF-alpha secretion. RESULT: Macrophage could bind and uptake oligochitosan, which was dependent on the temperature: the uptake proceeded rapidly at 37 degrees C and at 4 degrees C macrophage could only bind oligochitosan. EDTA decreased oligochitosan uptake. Trypsin treatment significantly reduced the internalization, and uptake was recovered by trypsin termination. Colchicine significantly inhibited the internalization process and was dose dependent. 0.1 mol/L mannose inhibited TNF-alpha expression induced by oligochitosan. CONCLUSION: Macrophage could uptake oligochitosan via mannose receptor mediated pinocytosis. Mannose receptor is crucial for the oligochitosan-induced macrophages activation.