An observation on long-term influence of middle ear bacterial infection on inner ear function and systemic immune reaction
ZOU Jing,BI Aifang,Yang Weiyan(Bethune International Peace Hospital,Shijiazhuang 050082, China)
【Abstract】ObjectiveTo understand whether long-term inner ear heat shock response related to heat shock protein(HSP70) caused by middle ear bacterial infection and the potential influence on inner ear function. Methods sixty BALB/c mice were randomly classified into 6 groups including Klebsiella pneumoniae(KP), Staphylococcus aureus, Bacillus pyocyaneus, Bacillus coli, Bacillus proteus and physiological saline control groups. On 135 days after injection, distortion product otoacoustic emissions(DPOAE) was tested and all the samples were collected, which were examined with light and electronic microscopes. HSP70 related molecule expression in inner ear, nuclear factor(NF)κ Bp65 characterization in mononuclear cell, anti-KP antibody and anti-membranous labyrinth proteins (MLP) were examined. Results No nuclear transfer of NF κ Bp65 was observed in any animal. Anti- KP antibody was detected in 30% (3/10) of Staphylococcus aureus group, 29% (2/7) of KP group, 33% (3/9) of Bacillus pyocyaneus group and 10% (1/10) of control group. Anti-MLP antibody was created in 20% (2/10) of Staphylococcus aureus group, 20% (2/10) of KP group, one each in Bacillus pyocyaneus group and control group respectively. Double positive antibody against KP and MLP were found in Staphylococcus aureus group and KP group. When analyzed with Western blot, all the positive bands were small molecules including strongest 26 000~30 000,medium degree 38 000~41 000 and weak 46 000~50 000 except for 68 000 in one case. There was only one significant DPOAE amplification decrease at 1 625 Hz (2f1-f2) in left ear of Bacillus pyocyaneus group and right ear of Bacillus proteus group. No abnormal phenomenon was found in inner ear both under light microscope and electronic microscope. No significant expression of HSP70 was observed in inner ears. Conclusion no long-term heat shock response related to HSP70 existed in the inner ear and the immune inner ear damage may be caused by multiplefactors.
【Key words】Otitis media;Bacterial infections;Labyrinth;Heat-shok proteins
1990年Harris等[1],用免疫转印方法测试双侧进行性感音神经性聋患者血清,可以与牛内耳提取物中相对分子质量为68 000的抗原发生反应。我们[2]观察到拟诊为自身免疫性感音神经性聋患者血清可以与豚鼠内耳提取物中多种抗原发生反应,包括分子量接近68 000的抗原。Billings等[3]报道,用离子交换和三磷酸腺苷纯化的该抗原可以和抗热休克蛋白(heat shock protein,HSP)70单克隆抗体反应,从而将该抗原与HSP70联系起来,认为该抗体即为抗HSP70抗体,并由此提出自身免疫性内耳病患者可能因曾患化脓性中耳炎,细菌HSP经圆窗膜进入内耳诱导机体产生抗HSP抗体,导致一系列内耳损伤。Bloch等[4,5]观察到双侧进行性感音神经性聋和梅尼埃病患者血清可以与重组的人和牛HSP70的C末端区427-461氨基酸片段反应,由此推测该表位可能是重要的病原。 我们[6]曾经通过动物模型观察到中耳急性细菌感染后可以诱导内耳HSP70相关表位分子的表达,以小分子为主。如果中耳细菌感染诱发的内耳热休克反应在内耳免疫损伤中起着重要作用的话,至少必须具备以下条件:即中耳细菌感染后机体持续产生抗HSP70抗体,且内耳持续高表达HSP70相关表位分子。我们分别用金黄色葡萄球菌(简称金葡菌)、变形杆菌、肺炎克雷白杆菌、大肠杆菌和绿脓杆菌感染BALB/c鼠,观察其对机体全身及内耳局部产生的长期影响。
材料与方法
一、材料
1.动物:一级BALB/c鼠80只,体重25~28 g,雌雄不拘;二级杂色豚鼠20只,体重300~400 g,雌雄不拘。以上动物均购自中国药品生物制品检定所实验动物繁育场(北京)。
2.致病菌:绿脓杆菌(产品号ATCC-27853)、变形杆菌(ATCC-49027)、大肠杆菌(ATCC-25922)、金黄色葡萄球菌(ATCC-25923)、肺炎克雷白杆菌(ATCC-26114-7)均购自中国生物制品鉴定所(北京)。
3.试剂:HRP-羊抗鼠IgG和HRP-羊抗兔IgG为进口分装,兔抗核因子κ B(p65)多克隆抗体、鼠抗哺乳类HSP70和鼠抗成纤维细胞生长因子受体单克隆抗体为美国Santa Cruz公司产品(SC-1060),SP试剂盒为美国Zymed公司产品。
4.主要仪器: 77000X Easy-TiterTM ELIFA System为美国Pierce公司生产,将其改造后用于进行外加电场固定液相分子快速斑点免疫(以下简称快速斑点免疫)分析,详细情况见另文报道。
二、方法
1.实验设计与动物分组:所有动物均经畸变产物耳声发射筛选,引出正常反应者饲养1周后实验。将合格的18只豚鼠按文献[6]报道方法制备膜迷路蛋白。将合格的60只BALB/c鼠随机分为6组,即肺炎克雷白杆菌组、金葡菌组、绿脓杆菌组、大肠杆菌组、变形杆菌组和生理盐水对照组,每组10只。
2.中耳感染模型建立:细菌培养及中耳感染模型的建立见文献[6]。注射致病菌后的动物在层流架上分笼饲养,观察135 d后取材。
3.畸变产物耳声发射测试:乙醚麻醉动物,在标准隔声室进行测试,分别于注射细菌前和处死动物前各测试1次。F1频率选取2 000、2 500、3 187、4 000、5 062、6 375 Hz,刺激声压级为65 dB SPL,F2频率为1.2倍F1,刺激声压级为55 dB SPL。计算各频率2F1-F2 DP振幅前后差值进行统计分析。
4.普通病理与电镜观察:用戊巴比妥钠腹腔注射(44 mg/kg)麻醉,心脏穿刺采血,分离单个核细胞及血浆。透射电镜组每组2只动物快速断头取双侧颞骨后刺破圆窗、卵圆窗,蜗尖钻孔用2.5%戊二醛固定(4℃),10% 乙二胺四乙酸脱钙,锇酸后固定,常规树脂包埋、超薄切 buffer saline,PBS)洗涤,甲醇双氧水室温孵育20 min。PBS洗涤,1∶20正常羊血清室温孵育30 min,1∶100兔抗核因子κ B(p65)抗体37℃孵育30 min。PBS洗涤,1∶100羊抗兔IgG同上孵育。PBS洗涤,二氨基联苯胺(diaminobenzidine tetrahydrochloride,DAB)显色。
7.抗肺炎克雷白杆菌抗体测试:用本实验室保存的应激后的肺炎克雷白杆菌抗原进行测试[6]。浓度为4.0 mg/ml,用快速斑点免疫分析检测鼠血中抗肺炎克雷白杆菌抗体,即先通过外加电场在10 min内将粗制细菌抗原快速吸附于硝酸纤维素膜,用含吐温20的PBS洗涤5 min,用含正常羊血清的1% BSA牛血清白蛋白封闭5 min,各孔加入1∶10稀释的待测鼠血浆50 μL,设空白对照,37℃摇浴10 min。取出硝酸纤维素膜,在PBS-吐温中高速摇洗2次,加入1∶1 000 HRP-羊抗鼠IgG,37℃高速摇浴10 min,同上摇洗2次,DAB显色(高速摇浴10 min)。
8.抗膜迷路蛋白抗体的测试:快速斑点免疫方法筛选用0.9 mg/ml粗制豚鼠膜迷路蛋白为抗原,同上在电场作用下吸附于硝酸纤维素膜,并用1∶10待测鼠血浆进行免疫分析。阳性血浆再进行免疫转印分析,血浆稀释倍数仍为1∶10,按照我们先前报道[7]的改良免疫转印方法进行测试。用Eagle Eye TMⅡ型电泳图像分析系统测试相对分子质量。
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