摘要
目的耐甲氧西林金黄色葡萄球菌(MRSA)感染日趋严重,免疫防治被寄予厚望。本研究旨在探索Toll样受体2(TLR2)激动剂Pam3Csk4预处理小鼠对MRSA攻击的保护作用。方法每只昆明小鼠用(25、50、100)μg Pam3Csk4尾静脉预处理12、24 h,小鼠尾静脉注射7×1010集落形成单位(CFU)/kg的MRSA(ATCC43300)。小鼠生存率按前24 h每2 h观察1次,后续每6 h记录小鼠存活情况,共观察1周。感染MRSA(3×108CFU/只)6 h后,菌落计数法观察肝、脾和肾等器官对MRSA的清除能力;3×108CFU/只MRSA攻击6、12、24 h后,ELISA检测小鼠血清中肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、γ干扰素(IFN-γ)和IL-10含量,实时荧光定量PCR(q PCR)检测MRSA攻击后小鼠脾脏TNF-α、IL-6、IFN-γ和IL-10的mRNA水平,以及Pam3Csk4预处理小鼠24 h后,CXC趋化因子配体1(CXCL1)和Fcγ受体Ⅲ(FcγRⅢ)表达量。结果 100μg Pam3Csk4预处理能显著提高MRSA攻击小鼠的生存率,与Pam3Csk4预处理时间呈时间依赖关系;MRSA攻击小鼠的生存时间与Pam3Csk4预处理剂量相关,50μg以上剂量Pam3Csk4预处理能显著提高MRSA攻击小鼠生存率至70%以上;与对照组比较,Pam3Csk4预处理小鼠血清中TNF-α在6 h和12 h均显著降低,24 h后2组间无显著差别;IL-6在处理6 h内显著降低,12 h和24 h后无显著差异,IFN-γ在24 h内均显著降低,而IL-10则无显著变化;Pam3Csk4预处理24 h后,脾脏中CXCL1和FcγRⅢ表达量均显著高于生理盐水组。结论 Pam3Csk4预处理对MRSA攻击小鼠具有保护作用。
Objective To evaluate the protective effect of pretreatment with Pam3Csk4,a Toll-like receptor 2（ TLR2）agonist,on mice against methicillin-resistant Staphylococcus aureus（ MRSA） infection. Methods Kunming mice were injected with Pam3Csk4（ 25,50,100 μg/mice） via tail vein. 12 and 24 hours later,the mice were inoculated with live MRSA（ 7 ×10^10CFU/kg,ATCC43300） via tail vein. All mice were observed at 2-hour intervals for the first 24 hours and 6-hour intervals for the rest time,and survival was monitored for at least 7 days. Bacterial burden in liver,spleen and kidney of the mice were estimated by colony counting on nutrient agar 6 hours after infection（ 3 × 10^8 CFU/mice,ATCC43300）. In addition,6,12 and24 hours after MRSA challenge,the concentrations of tumor necrosis factor α（ TNF-α）,interleukin 6（ IL-6）,interferon γ（ IFN-γ） and IL-10 were measured by ELISA,and the mRNA levels of these cytokines were detected by fluorescence quantitative PCR（ q PCR）. Finally,24 hours after being pretreated with Pam3Csk4,mRNA levels of CXC chemokine ligand 1（ CXCL1） and Fcγ receptor Ⅲ（ FcγRⅢ） in spleen of the mice were evaluated by q PCR. Results Compared with normal saline-pretreated mice,we found that mice pretreated with the Pam3Csk4（ 100 μg/mice） had higher survival in sepsis models caused by MRSA in dose- and time-dependent manners,and Pam3Csk4（ over 50 μg/mice）-pretreated mice had a survival rate more than 70%. In addition, the protein and mRNA levels of TNFα were markedly reduced in Pam3Csk4-pretreated mice at 6 and 12 hours,but not different from the controls at 24 hours post-infection. While IL-6 at protein and mRNA levels decreased in Pam3Csk4-pretreated mice only at 6 hours post-infection. Both protein and mRNA levels of IFN-γ greatly decreased in Pam3Csk4-pretreated mice compared with those of the control group. However,IL-10 level was unchanged between the two groups at all time points. Further studies showed that the mRNA levels of CXCL1 and FcγR�
出处
《细胞与分子免疫学杂志》
CAS
CSCD
北大核心
2016年第2期212-216,共5页
Chinese Journal of Cellular and Molecular Immunology
基金
国家自然科学基金(81360454)
江西省自然科学基金(20132BAB205049)
