Trune Dennis R, Kempton Beth, Hausman Frances A, Larrain Barbara E, MacArthur Carol J
Oregon Hearing Research Center, Department of Otolaryngology Head & Neck Surgery, Oregon Health & Science University, Portland, OR, USA.
Oregon Hearing Research Center, Department of Otolaryngology Head & Neck Surgery, Oregon Health & Science University, Portland, OR, USA.
Hear Res. 2015 Aug;326:49-58. doi: 10.1016/j.heares.2015.04.006. Epub 2015 Apr 25.
Although the inner ear has long been reported to be susceptible to middle ear disease, little is known of the inflammatory mechanisms that might cause permanent sensorineural hearing loss. Recent studies have shown inner ear tissues are capable of expressing inflammatory cytokines during otitis media. However, little quantitative information is available concerning cytokine gene expression in the inner ear and the protein products that result. Therefore, this study was conducted of mouse middle and inner ear during acute otitis media to measure the relationship between inflammatory cytokine genes and their protein products with quantitative RT-PCR and ELISA, respectively. Balb/c mice were inoculated transtympanically with heat-killed Haemophilus influenzae and middle and inner ear tissues collected for either quantitative RT-PCR microarrays or ELISA multiplex arrays. mRNA for several cytokine genes was significantly increased in both the middle and inner ear at 6 h. In the inner ear, these included MIP-2 (448 fold), IL-6 (126 fold), IL-1β (7.8 fold), IL-10 (10.7 fold), TNFα (1.8 fold), and IL-1α (1.5 fold). The 24 h samples showed a similar pattern of gene expression, although generally at lower levels. In parallel, the ELISA showed the related cytokines were present in the inner ear at concentrations higher by 2-122 fold higher at 18 h, declining slightly from there at 24 h. Immunohistochemistry with antibodies to a number of these cytokines demonstrated they occurred in greater amounts in the inner ear tissues. These findings demonstrate considerable inflammatory gene expression and gene products in the inner ear following acute otitis media. These higher cytokine levels suggest one potential mechanism for the permanent hearing loss seen in some cases of acute and chronic otitis media.
尽管长期以来一直报道内耳易患中耳疾病，但对于可能导致永久性感音神经性听力损失的炎症机制却知之甚少。最近的研究表明，在中耳炎期间内耳组织能够表达炎性细胞因子。然而，关于内耳中细胞因子基因表达及其产生的蛋白质产物的定量信息却很少。因此，本研究在急性中耳炎期间对小鼠的中耳和内耳进行了检测，分别用定量逆转录聚合酶链反应（RT-PCR）和酶联免疫吸附测定（ELISA）来测量炎性细胞因子基因与其蛋白质产物之间的关系。通过鼓膜穿刺给Balb/c小鼠接种热灭活的流感嗜血杆菌，然后收集中耳和内耳组织用于定量RT-PCR微阵列或ELISA多重阵列检测。几种细胞因子基因的信使核糖核酸（mRNA）在6小时时在中耳和内耳中均显著增加。在内耳中，这些细胞因子包括巨噬细胞炎性蛋白-2（MIP-2，增加448倍）、白细胞介素-6（IL-6，增加126倍）、白细胞介素-1β（IL-1β，增加7.8倍）、白细胞介素-10（IL-10，增加10.7倍）、肿瘤坏死因子α（TNFα，增加1.8倍）和白细胞介素-1α（IL-1α，增加1.5倍）。24小时的样本显示出类似的基因表达模式，尽管总体水平较低。与此同时，ELISA显示相关细胞因子在内耳中的浓度在18小时时比原来高出2至122倍，在24小时时略有下降。用针对其中多种细胞因子的抗体进行免疫组织化学检测表明，它们在内耳组织中的含量更高。这些发现表明，急性中耳炎后内耳中存在相当程度的炎症基因表达和基因产物。这些较高的细胞因子水平提示了在一些急性和慢性中耳炎病例中出现永久性听力损失的一种潜在机制。
