Proinflammatory cytokines expression in noise-induced damaged cochlea
Proinflammatory cytokines expression in noise-induced damaged cochlea
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DOI：
10.1002/jnr.20764
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发表时间：
2006-03-01
影响因子：
4.2
通讯作者：
Okano, H
中科院分区：
文献类型：
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作者：
Fujioka, M;Kanzaki, S;Okano, H
最近的研究表明，内耳在包括噪声过度刺激在内的各种损伤条件下都会发生炎症反应。我们评估了致炎细胞因子在噪声暴露的大鼠耳蜗组织中的时间依赖性表达。在检测到的几种细胞因子中，实时定量RT-PCR显示，噪声暴露后3h，白介素1β(IL-1β)和白介素6(IL-6)显著诱导，并迅速下调至基础水平。噪声暴露后即刻，肿瘤坏死因子-α(TNF-α)也略有上调。免疫组织化学分析显示，IL-6在螺旋韧带外侧有明显表达。序贯表达分析表明，IL-6免疫反应最初见于侧壁细胞的胞浆，包括IV型和III型纤维细胞，并在整个侧壁扩大，最后扩展到血管纹。由于LBA-1染色阴性，早期IL-6的表达不是由于巨噬细胞或小胶质细胞的激活。噪声暴露后12小时和24小时，螺旋神经节神经元中也可检测到IL-6。我们的数据表明，在噪声过度刺激的早期阶段，耳蜗会产生促炎细胞因子，包括TNF-α、IL-1β和IL-6。IL-6在螺旋韧带、血管纹和螺旋神经节神经元中有表达。这些细胞因子由耳蜗结构本身对噪声暴露作出反应，可能启动炎症反应，并在噪声诱导的耳蜗损伤机制中发挥一定作用。(C)2006年Wiley-Liss，Inc.
Recent studies have showed that inflammatory responses occur in inner ear under various damaging conditions including noise-overstimulation. We evaluated the time-dependent expression of proinflammatory cytokines in noise-exposed rat cochlea. Among several detected cytokines, real-time RT-PCR showed that interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) were significantly induced 3 hr after noise exposure, and quickly downregulated to the basal level. Tumor necrosis factor-alpha (TNF-alpha) was also slightly upregulated immediately after noise exposure. Immunohistochemical analysis showed that IL-6 expression was distinctively induced within the lateral side of the spiral ligament. Sequential expression analysis showed that IL-6 immunoreactivity was initially found in the cytoplasm of lateral wall cells, including Type IV and III fibrocytes, and expanded broader throughout the lateral wall, finally to the stria vascularis. Because of the negative lba-1 staining, IL-6 expression in the early-phase was not due to macrophage or microglia activation. IL-6 was also detected in spiral ganglion neurons at 12 and 24 hr after noise exposure. Our data demonstrates the production of proinflammatory cytokines, including TNF-alpha, IL-1 beta, and IL-6, in early phase of noise overstimulated cochlea. IL-6 expression was observed in the spiral ligament, stria vascularis, and spiral ganglion neurons. These cytokines, produced by the cochlear structure itself in response to noise exposure, may initiate an inflammatory response and have some role in the mechanism of noise-induced cochlear damage. (C) 2006 Wiley-Liss, Inc.