实验性结肠炎大鼠Toll样受体2和4表达及益生菌治疗的作用

Expression of Toll-like receptor 2 and 4 on colons of experimental colitis rats and the therapeutic effects of probiotics

目的探讨和分析实验性结肠炎大鼠结肠Toll样受体2（TLR2）和Toll样受体4（TLR4）的表达及意义，并分析益生菌治疗的作用。方法30只雄性Wistar大鼠均分为正常对照组（NC组）、模型对照组（UC组）和益生菌治疗组（PC组）。UC和PC组建立2，4，6-三硝基苯磺酸（TNBs）实验性结肠炎大鼠模型。PC组大鼠给予双歧三联活菌悬液（2．2×10^9CFU／只）治疗，1次／d，共4周。光镜下观察肠黏膜炎性反应并评分。Western印迹法和实时荧光定量PCR法检测大鼠结肠TLR2和TLR4蛋白及mRNA表达，分析其变化及益生菌治疗的作用。结果NC、PC和UC组炎性反应评分分别为4．35±0．88、10．25±1．36和7．94±0．85。PC组炎性反应评分较UC组明显改善（P〈0．05），但高于NC组水平（P〈0．01）。NC、UC、PC组TLR2和TLR4蛋白表达水平分别为10．26±4．24、47．20±4．62、36．64±3．67和8．16±4．50、25．84±4．46、19．71±3．28。二者在UC组的表达明显高于NC组（P〈0．01）和PC组（P〈0．05），PC组高于NC组（P〈0．01）。NC、UC、PC组TLR2和TLR4mRNA表达水平分别为240±140、10570±2690、6640±1420和210±110、8580±2710、5290±1540。二者在UC组的表达明显高于PC组（P〈0．05）和NC组（P〈0．01），PC组高于NC组（P〈0．01）。结论实验性结肠炎大鼠结肠TLR2和TLR4表达明显增高，提示肠腔内抗原摄取增多。双歧三联活菌可明显降低二者的表达水平，提示该益生菌可能通过降低TLR2和TLR4表达减少肠腔抗原的摄取。

Objective To investigate the protein and mRNA expressions of Toll-like receptor 2 （TLR2） and Toll-like receptor 4 （TLR4） on colons of rats with trinitrobenzene sulfonic acid （TNBS）- induced colitis, and to evaluate the effects of probiotics. Methods Thirty male Wistar rats were randomly divided into normal control group （NC group）, model control group（UC group） and probiotics-treated group（PC group）. The experimental colitis was induced by TNBS/ethanol enema. Rats in PC group were fed with Bifico [live probiotics of combined bifidobacterium（Bif）, lactobacillus（Lac） and enterococcus] by 2.2 ×10^9 CFU/d for 4 weeks. Inflammatory scores were studied. Expressions of protein and mRNA of TLR2 and TLR4 were measured by Western blot and real-time quantitative polymerase chain reaction （PCR）, respectively. Results Inflammatory scores in NC group, UC group and PC group were 4.35 ± 0.88, 10.25 ± 1.36 and 7.94 ± 0.85, respectively. The inflammatory scores in PC group were decreased compared with that in UC group （P 〈 0.05）, whilst higher than that in NC group （P 〈 0.01）. Protein expressions of TLR2 and TLR4 in NC, UC and PC groups were 10.26±4.24, 47.20±4. 62,36.64± 3.67 and 8.16±4.50, 25.84±4.46, 19.71±3.28, respectively. Protein expressions of TLR2 and TLR4 in UC group were higher than those in PC group （P〈 0.05） and in NC group （P 〈 0.01）, which in PC group were higher than those in NC group （P 〈 0.01）. mRNA expressions（copies） of TLR2 and TLR4 in NC, UC and PC groups were TLR2： 240±140, 10 570±2690, 6640±1420 and TLR4： 210±110, 8580 ±2710, 5290±1540, respectively, mRNA expressions of TLR2 and TLR4 in UC group were higher than those in PC group （P 〈 0.05 ） and in NC group （P 〈 0.01 ）, which in PC group were higher than those in NC group （P 〈 0.01）. Conclusions Expressions of TLR2 and TLR4 were increased significantly in TNBS-induced colitis rats, suggesting more antigens in lumen are taken. Bifico may decrease the expressions of TLR2 and TLR4 to reduce antigen-taking in lumen of rats with TNBS-induced colitis.