表皮葡萄球菌感染导致新生小鼠脑损伤机制的研究  

Study on the mechanism of brain damage caused by Staphylococcus epidermidis in mice

作　　者：乔丽丽[1] 申建伟[1] 胡诤 

机构地区：[1]上海市松江区中心医院,上海201600

出　　处：《临床儿科杂志》2015年第3期280-283,共4页Journal of Clinical Pediatrics

基　　金：上海市松江区卫生局资助项目(No.2012-Ⅲ-10)

摘　　要：目的探讨表皮葡萄球菌（SE）感染引起新生小鼠脑损伤的机制。方法出生第1天新生小鼠共80只,分为SE组、生理盐水（NS）组、对照组,其中SE组48只,NS组及对照组各16只。SE组静脉注射108/ml的SE 50μl,NS组给予等量的NS,对照组不予任何处理。在注射后不同时间点（6 h、24 h、72 h、5 d、7 d）取血、脾、脑过夜培养后做细菌菌落（CFU）计数;在24 h和72 h取脑组织石蜡包埋后连续切片,用于离子钙接头蛋白抗体（Iba-1）免疫组化染色;在6 h和24 h取脑组织用酶联免疫吸附试验测定肿瘤坏死因子（TNF-α）、白介素-1β（IL-1β）、IL-5、IL-6。结果注射后不同时间点,SE组小鼠脑组织中均未发现细菌,血和脾中6 h菌落计数最高,24 h后迅速下降。在注射后24 h、72 h,SE组、NS组和对照组三组之间大脑中Iba-1阳性细胞数的差异有统计学意义（H=75.56、69.54,P均〈0.001）;其中SE组高于NS组和对照组,差异有统计学意义（P均〈0.05）。各组在24 h与72 h两个时间点,大脑中Iba-1阳性细胞数差异无统计学意义（P均〉0.05）。在注射后6 h、24 h,三组之间大脑TNF-α、IL-1β、IL-5和IL-6水平差异有统计学意义（H=59.07-319.34,P均〈0.001）;其中SE组大脑中各细胞因子含量均高于NS组和对照组,差异有统计学意义（P〈0.05）。SE组在注射后24 h,与6 h时相比,TNF-α、IL-1β、IL-5和IL-6水平均有下降,两时间点差异均有统计学意义（P〈0.01）。结论 SE引起的新生小鼠的脑损伤可能通过激活脑内小胶质细胞,同时分泌大量的细胞因子而引起。Objectives To study the mechanism of brain damage caused by Staphylococcus epidermidis（SE） in mice.Methods A total of 80 neonatal mice of postnatal day 1（PND1） were divided into SE group（48 mice）,normal saline（NS） group（16 mice） and control group（16 mice）.Mice in SE group were intravenously injected with 50 μl SE（108/ml）.Mice in NS group were given 50 μl NS.Mice in control group were not intervened.At different time points after SE injection（6 h,24 h,72 h,5 d,7 d）,the CFU of brain,blood,and spleen were calculated.Serial sections of paraffin-embedded brain tissue were used for detection of ionized calcium-binding adaptor moleculor1（Iba-1） by immunohistochemical staining.The positive cells were calculated.ELISA was used to measure the levels of tumor necrosis factor alpha（TNF-α）,interleukin-1β（IL-1β）,interleukin-5（IL-5）,interleukin-6（IL-6） of brain at 6 h and 24 h after SE injection.Results There was no SE in brain in different time points.The CFU was at the highest level at 6 h and then decreased after 24 h in blood and spleen.The Iba-1 positive cells in SE group were significantly increased compared to NS group and control group at 24 h and 72 h（P〈0.05）.There was no difference of Iba-1 positive cells between 24 h and 72 h after SE injection（P〉0.05）.The levels of TNF-α,IL-1β,IL-5,and IL-6 were significantly higher in SE group than those in NS and control at 6 h and 24 h（P〈0.05）.The levels of TNF-α,IL-1β,IL-5,and IL-6 were significantly lower in SE group at 24 h than those in SE group at 6 h（P〈0.01）.Conclusions It is suggested that cytokines produced by microglias may be the mediators of SE-caused brain damage.

关 键 词：表皮葡萄球菌 脑组织 新生小鼠 

分 类 号：R742[医药卫生—神经病学与精神病学]