乳酸菌联合中链甘油三酯或葡萄糖对LPS诱导的小鼠肠道炎症的影响

EFFECTS OF LACTOBACILLUS COMBINED WITH MEDIUM-CHAIN TRIGLYCERIDES OR GLUCOSE ON INTESTINAL INFLAMMATION INDUCED BY LPS IN MICE

目的观察和分析乳酸菌联合中链甘油三酯(medium-chaintriglycerides,MCT)或葡萄糖对脂多糖(lipopolysaccharides,LPS)诱导的小鼠肠道急性炎症的影响,为重症感染患者提供肠内营养参考。方法取12w龄雄性C57BL/6J小鼠30只,测量空腹体质量后随机分5组:MCT组(乳酸菌+MCT)、GLU组(乳酸菌+葡萄糖)、LAB组(乳酸菌)、LPS组(LPS损伤对照)和EPT组(正常对照)。除了EPT组腹腔注射生理盐水外,其余4组腹腔注射3.5mg/kg LPS。24h后根据分组分别灌胃小鼠(MCT组:0.1ml生理盐水+0.03g乳酸菌+0.114g MCT粉;GLU组:0.1ml生理盐水+0.03g乳酸菌+0.2g葡萄糖;LAB组:0.1ml生理盐水+0.03g乳酸菌;LPS组:0.1ml生理盐水;EPT组:0.1ml生理盐水。8 d后取小鼠腹主动脉血及小肠组织,测定细胞因子水平和TLR4信号通路中相关分子的mRNA表达,并进行小肠组织病理切片观察。研究期间每日测量小鼠体质量。结果研究结束时,除了LPS组,其余4组小鼠体重均升高,MCT组显著高于GLU、LAB和LPS组(P<0.05),而与EPT组差异无统计学意义(P>0.05);MCT组血清和小肠组织中TNF-α、IL-1β、IL-6、MCP-1水平及小肠组织中TLR4、MyD88、NF-κB的mRNA表达均显著低于GLU、LAB和LPS组(P<0.05),而与EPT组差异无统计学意义(P>0.05)。小肠组织病理切片结果显示:除EPT组,其余4组小鼠小肠粘膜均有不同程度的损伤,以LPS损伤组损伤最明显,LAB组次之,GLU组处于中等水平,MCT组损伤较轻。结论乳酸菌联合中链甘油三酯对LPS诱导的肠道炎症的修复作用优于乳酸菌联合葡萄糖治疗,机制可能为在营养肠道的同时,此配方抑制肠道TLR4信号传导途径相关因子表达,减少促炎细胞因子释放,从而减轻肠道炎症反应。[营养学报,2020,42(3):255-259,265]

Objective To study the effects of lactobacillus combined with medium-chain triglycerides(MCT) or glucose on acute intestinal inflammation induced by lipopolysaccharides(LPS) in mice. Methods Twelve-week-old male C57 BL/6 J mice(n=30) were randomly divided into 5 groups after fasting weight measurement: MCT group(lactobacillus+MCT), GLU group(lactobacillus+glucose), LAB group(lactobacillus), LPS group(LPS injury control) and EPT group(normal control). Mice in EPT group were injected with saline intraperitoneally, while mice in other four groups were all injected intraperitoneally with LPS(3.5 mg/kg/bwt). After 24 h, mice were gavaged according to their different treatments(MCT group:0.1 ml 0.9%NaCl + 0.03 g lactobacillus +0.114 g MCT;GLU group:0.1 ml 0.9%NaCl +0.03 g lactobacillus +0.2 g glucose;LAB group:0.1 ml 0.9%NaCl +0.03 g lactobacillus;LPS group:0.1 ml 0.9%NaCl;EPT group:0.1 ml 0.9%NaCl). Eight days later, blood samples and small intestine tissues were collected and the levels of inflammation factors and the mRNA expression of related molecules in TLR4 pathway were determined. Biopsy of the small intestines was observed. Mice were weighed daily throughout the experiment. Results At the end of the study, except for the LPS group, body weight of the other four groups were all increased, and the MCT group was significantly higher than the GLU, LAB and LPS groups(P<0.05), but there was no significant difference compared to the EPT group(P>0.05). The concentrations of TNF-α,IL-1β,IL-6 and MCP-1 in serum and small intestine, and the mRNA expression of TLR4, MyD88 and NF-κB in small intestine tissue were significantly lower than those of the GLU, LAB, and LPS groups(P<0.05), but there was no significant difference compared to the EPT group(P>0.05). Pathological observation of small intestine tissue showed that mice in the LPS group had the worst injury, LAB group was a little worse, GLU group was in the medium, and MCT group had no obvious injury. Conclusion Lactobacillus combined with medium-chain triglycerides had better protective effect than glucose on intestinal injury in LPS treated mice. The mechanism may be via reducing inflammatory factors release by inhibiting TLR4 signaling pathway.[ACTA NUTRIMENTA SINICA, 2020,42(3):255-259,265]