Heinrich Ulf-Rüdiger, Selivanova Oxana, Schmidtmann Irene, Feltens Ralph, Brieger Jürgen, Mann Wolf J
Department of Otolaryngology, Head and Neck Surgery, Johannes Gutenberg University of Mainz, Medical School, Langenbeckstrasse 1, 55131 Mainz, Germany.
Acta Otolaryngol. 2010 Mar;130(3):358-65. doi: 10.1080/00016480903168066.
Changes in the metabolism of arachidonic acid (AA) might be part of a noise-induced compensatory mechanism with regional specificity.
The released imbalance of prostaglandins and leukotrienes, both AA metabolites, might result in altered blood flow regulation in the inner ear and probably contributes to noise-induced hearing loss. The aim of this study was to gain further information about noise-dependent changes in AA metabolism in the mammalian cochlea.
In this prospective animal study, 10 male guinea pigs were exposed to tone bursts for 1 h at 70 dB sound pressure level (SPL) (n = 5) or 90 dB SPL (n = 5). Five animals were used as controls. Alterations in cyclooxygenase 1 (COX-1) and 5-lipoxygenase (5-LO) expression were determined by quantitative immunohistochemical analysis in 11 cochlear regions.
COX-1 expression was decreased after both 70 dB SPL and 90 dB SPL exposure in most cell types of the organ of Corti and increased in the nerve fibers of the osseous spiral lamina. 5-LO was lowered after 90 dB SPL exposure, preferentially in the third cochlear turn in the organ of Corti, in the first and second turn in spiral ganglion cells, and in all turns in the stria vascularis.
花生四烯酸（AA）代谢的变化可能是噪声诱导的具有区域特异性的代偿机制的一部分。
前列腺素和白三烯这两种AA代谢产物的释放失衡，可能导致内耳血流调节改变，并可能导致噪声性听力损失。本研究的目的是进一步了解哺乳动物耳蜗中AA代谢的噪声依赖性变化。
在这项前瞻性动物研究中，10只雄性豚鼠分别暴露于70分贝声压级（SPL）（n = 5）或90分贝SPL（n = 5）的短音脉冲1小时。5只动物作为对照。通过定量免疫组织化学分析确定11个耳蜗区域中环氧合酶1（COX-1）和5-脂氧合酶（5-LO）表达的变化。
在70分贝SPL和90分贝SPL暴露后，Corti器的大多数细胞类型中COX-1表达降低，而骨螺旋板的神经纤维中COX-1表达增加。90分贝SPL暴露后5-LO降低，主要在Corti器的耳蜗第三圈、螺旋神经节细胞的第一和第二圈以及血管纹的所有圈中。
