中文摘要：

目的：研究嗜酸乳杆菌（Lactobacillus acidophilus）NCFM胞外多糖对小鼠免疫相关基因的调控作用。方法：通过构建小鼠模型,对小鼠脏器系数进行分析,提取肠组织RNA,采用Real-time RT-PCR方法对免疫相关基因chemokine（C-C motif）ligand 2（CCL2）和interleukin 18（IL18）的表达情况进行分析。结果：脏器系数随着天数的增加而增加,实验组的脏器系数较对照组相比,显著增加。在2个免疫相关基因中,随着时间的延长,IL18和CCL2呈现出先迅速增加后减少的趋势,同时均在第4天表达量达到最大值,且与对照组相比差异极显著（P〈0.01）。结论：胞外多糖可以提高小鼠免疫脏器的质量,并且能够引起免疫相关基因出现特定表达变化,对小鼠机体的免疫调控具有一定的作用。

英文摘要：

Objective：Exopolysaccharide（EPS） is a metabolic product of probiotics with antitumor,immunomodulatory and antioxidant functions.The aim of this study is to explore the effect of EPS produced by Lactobacillus acidophilus NCFM on immune-related genes in mice.Methods：Viscera coefficients were analyzed through mouse model.Real-time PCR was used to evaluate the expression of immune-related genes in mice after extracting total RNA from intestinal tissues.Results：The results indicated that the viscera coefficients revealed an increase with the extension of time and a significant difference in viscera coefficients between experimental group and control group（P＆lt;0.01）.The expression of immune-related genes such as CCL2 and IL18 genes exhibited an initial increase and a final decrease with the extension of time and had the highest level on the 4th day.Similarly,a significant difference in the expression of these genes between experimental group and control group was observed（P＆lt;0.001）.Conclusion：EPS can increase the relative weight of immune viscera,and affect the differential expression of immune-related genes.EPS produced by L.acidophilus NCFM can enhance immune function.