【摘要】 为明确鼠李糖乳杆菌GR-1(L.rhamnosus GR-1)在大肠杆菌感染原代奶牛子宫内膜上皮细胞(BEECs)过程中调节炎性反应的机制，本试验将BEECs分为4个组，分别是对照组(加入5 mL培养基)、E.coli攻菌组(加入5 mL浓度为1×10~5 CFU/mL大肠杆菌)、L.rhamnosus GR-1单独处理组(提前3 h加入5 mL浓度为1×10~7 CFU/mL L.rhamnosus GR-1)和L.rhamnosus GR-1保护组(加入5 mL浓度为1×10~7 CFU/mL L.rhamnosus GR-1孵育3 h后去掉上清液，再加入5 mL浓度为1×10~5 CFU/mL大肠杆菌);采用光学显微镜观察E.coli对BEECs形态的损害情况，实时荧光定量PCR检测相关基因的转录水平，Western blot检测TLR2和NF-κB2的蛋白表达。结果显示，E.coli攻菌6 h后，与E.coli攻菌组相比，L.rhamnosus GR-1保护组BEECs形态保持完整，且TLR2、TLR4、TNF-α mRNA表达量极显著下调(P<0.01或P<0.001),TLR2和NF-κB2的蛋白水平也极显著下降(P<0.001)。结果表明，L.rhamnosus GR-1可能通过TLRs下调BEECs的炎性因子表达，从而缓解E.coli感染造成的奶牛子宫内膜上皮细胞损伤，为奶牛子宫内膜炎的防治提供数据参考。更多还原

【Abstract】 To investigate the mechanism of Lactobacillus rhamnosus GR-1 regulating inflammatory response in bovine endometrium epithelial cells(BEECs) challenged with Escherichia coli(E. coli), this study divided BEECs into four groups:(1) CONT group: cells were challenged with 5 mL culture medium;(2) ECOL group: cells were challenged with 5 mL 1×10~5 CFU/mL E. coli suspension;(3) LRGR group: cells were challenged with 5 mL 1×10~7 CFU/mL L. rhamnosus GR-1 suspension;(4) LRGR + ECOL gourp: cells were pretreated with 5 mL 1×10~7 CFU/mL L. rhamnosus GR-1 for 3 h before challenged with 5 mL 1×10~5 CFU/mL E. coli. The damages in cell morphology were observed by optical microscope. The expressions of relevant mRNA and protein related to NF-κB pathway were detected by quantitative real-time PCR and Western blot, respectively. The results showed that after challenge with E. coli for 6 h, compared with ECOL group, the morphology of BEECs in LRGR+ECOL group was normal, the mRNA expressions of TLR2, TLR4 and TNF-α in BEECs were significantly down-regulated(P < 0.01 or P < 0.001), and the protein expressions of TLR2 and NF-κB2 in BEECs were significantly decreased(P < 0.001). Thus, L. rhamnosus GR-1 could down-regulate inflammatory factor expression in BEECs through TLRs, and alleviate damage caused by E. coli. This data provides useful technical details for the prevention and treatment of bovine endometritis.更多还原