牛至精油及肉桂精油对弗氏柠檬酸杆菌感染小鼠的预防作用研究

Study on preventive effect of essential oils of oregano and cinnamon in mice infected with Citrobacter freundii

试验旨在研究弗氏柠檬酸杆菌对小鼠的致病性及牛至精油和肉桂精油对小鼠抵抗弗氏柠檬酸杆菌感染的预防效果。致病性试验将30只小鼠随机分为5组,对照组小鼠腹腔注射0.2 mL生理盐水,1/2倍剂量组、1倍剂量组、2倍剂量组、4倍剂量组小鼠腹腔注射2.5×10^(9)、5.0×10^(9)、1.0×10^(10)、2.0×10^(10)CFU/mL的弗氏柠檬酸杆菌菌液(100μL/g体重),观察感染后小鼠临床症状及死亡情况。预防试验将30只小鼠随机分为对照组、模型组、牛至精油组、肉桂精油组及复合精油组(牛至精油和肉桂精油组合)。小鼠口服精油7 d后腹腔注射弗氏柠檬酸杆菌,观察小鼠脏器载菌量、空肠炎症细胞因子含量及空肠病理变化。结果显示,小鼠感染弗氏柠檬酸杆菌后出现眼球充血等临床症状后抽搐死亡。精油能够提高小鼠存活率,减少脏器载菌量和炎症细胞因子含量,缓解小鼠肠道损伤。研究表明,弗氏柠檬酸杆菌对小鼠具有较强致病性,精油能够提高小鼠的肠道屏障功能,阻止弗氏柠檬酸杆菌在小鼠肝脏及脾脏的定植,降低小鼠空肠促炎细胞因子的含量,提高小鼠的存活率。

The study was to investigate the pathogenicity of Citrobacter freundii in mice and the preventive effect of oregano and cinnamon essential oils on the resistance of mice to Citrobacter freundii infection.For pathogenicity test,30 mice were randomly divided into five groups.The mice in the control group were intraperitoneally injected with 0.2 mL normal saline.Mice in 1/2 times dose group,1 times dose group,2 times dose group and 4 times dose group were intraperitoneally injected with 2.5×10^(9),5.0×10^(9),1.0×10^(10),2.0×10^(10)CFU/mL of Citrobacter freundii bacterial solution(100μL/g body weight).In the prevention test,mice were randomly divided into the control group,the model group,the oregano essential oils group,the cinnamon essential oils group and the combination essential oils group(oregano and cinnamon essential oil combination),mice were injected intraperitoneally with Citrobacter freundii after 7 d of oral administration of essential oils,and the bacterial load,the levels of jejunal inflammatory cytokines and the pathological changes in the jejunum were observed.The results showed that mice infected with Citrobacter freundii showed clinical signs such as eye congestion and then convulsions and died.Essential oils prophylaxis improved the survival rate of mice,reduced the levels of organ carriage and inflammatory cytokines,and increased the number of intestinal villi and thickened the intestinal wall.The experiment indicates that Citrobacter freundii is highly pathogenic to mice.Essential oils prophylaxis can strengthen the intestinal barrier of mice,prevent the colonization of the liver and spleen of mice infected by Citrobacter freundii,reduce the levels of pro-inflammatory cytokines in the jejunum of mice,and thus improve the survival rate of mice.