中文摘要：

目的初步探讨PEG修饰CLP-19预保护小鼠对LPS刺激的免疫应答作用。方法相同剂量（2 mg/kg）的PEG-CLP-19或CLP-19分别于20、10、5、0 h前作用于小鼠,再给予亚致死剂量LPS,分别于LPS刺激前（0 h）或刺激后4 h分离小鼠血清,ELISA法测定炎性因子MCP-1、TNF-α及IL-10的变化情况。组织病理学观察小鼠肺的病变情况。结果单独给予PEG-CLP-19或CLP-19各时间组的小鼠TNF-α及IL-10无显著变化作用,但均可上调MCP-1的表达,尤其以提前20 h给予最为显著;提前20、10、5 h或同时给予PEG-CLP-19/CLP-19均可显著下调TNF-α、IL-10和MCP-1的表达,但同时给药效果最为显著（P〈0.01）,PEG-CLP-19调节能力显著强于CLP-19（P〈0.05）。结论 PEG-CLP-19预处理小鼠可显著提高小鼠MCP-1的表达,且该作用呈时间依赖效应,并抑制小鼠机体对LPS的免疫应答,从而降低机体炎症水平。因此可作为临床治疗脓毒症的潜在治疗药物。

英文摘要：

In order to investigate the effects of PEG-modified CLP-19 on LPS induced immune response in vivo, the sub-lethal LPS model were applied to mice at 20, 10, 5 and 0 hours respectively after PEG-CLP-19（2 mg/kg） or CLP-19（2 mg/kg） pretreatment. Mouse sera were collected at 0 or 4 hours after LPS stimulation. The concentration of MCP-1, TNF-α and IL-10 were measured by ELISA, and the histopathological changes in lung were evaluated. Our results showed that there were no significant difference of TNF-α or IL-10 levels in mice treated with PEG-CLP-19 or CLP-19, while the level of MCP-1 was increased, especially in mice pretreated at 20 hours before. The expression levels of TNF-α, IL-10, and MCP-1 were significantly down-regulated in LPS-stimulated mice at 20, 10, and 5 hours pretreatment with PEG-CLP-19 or CLP-19, especially on the time when PEG-CLP-19 or CLP-19 co-administrated with LPS（P〈0.01）. Compared with CLP-19, PEG-CLP-19 showed more significantly down-regulating effects at the same dose（P〈0.05） in down regulating inflammation mediators. In conclusion, PEG-CLP-19 can significantly increase the expression of MCP-1 in a time-dependent manner, and suppress LPS-induced immune response in organism, thus can be considered as a potential therapeutic agent to treatment of sepsis.