高压氧治疗噪声性耳聋的实验研究

An experimental study on hyperbaric oxygen therapy for noise-induced hearing loss

目的通过探讨高压氧治疗噪声性耳聋的时间点和疗效的关系,为临床应用提供参考。方法取清洁级健康白色红目、ABR阈值正常的豚鼠50只,雌雄不限,体重250～300g。随机分成3组,空白对照组、噪声组、噪声＋高压氧治疗组（压力为2ATA,疗程10天）,分别于噪声暴露后即刻、7天后、14天后给予高压氧治疗。另取5只作为噪声暴露后即刻取材组。给予脉冲噪声（压力峰值142d B SPL,脉宽0.25ms）连续暴露100次。于脉冲噪声暴露前、暴露后即刻及高压氧治疗2次后、治疗6次后、治疗10次后测听性脑干反应（ABR）。治疗结束后通过对炎症因子及氧自由基的测定观察耳蜗的代谢变化。结果与噪声组相比,噪声暴露后即刻高压氧治疗可以减轻16 k Hz的ABR阈值,有统计学意义（P〈0.05）。噪声暴露7天后给予高压氧治疗在click、4k Hz、8 k Hz、16 k Hz上的ABR阈值比噪声组低（P〈0.05）。噪声暴露14天后给予高压氧治疗在各频率上与噪声组相比,均无统计学差异,甚至在click、4k Hz时高压氧治疗组ABR阈值高于噪声组。噪声＋高压氧治疗组的8-OHd G、TNF-α、IL-1β含量较噪声组低（P〈0.05）,噪声＋高压氧治疗组的HIF-1α含量虽较噪声组低,但无统计学意义。结论高压氧在治疗噪声性耳聋方面有显著效果,噪声暴露7天后给予高压氧治疗效果最好,噪声暴露14天后不但效果差,有的甚至有不利影响。

Objective To study the timing and efficacy of hyperbaric oxygen therapy（HBOT） in treating noise-induced hearing loss, for potential translation to clinical applications. Methods Fifty healthy guinea pigs with normal ABR thresholds, weighing 250-300 g were used. Forty five guinea pigs were randomly divided into 3 groups, i.e. control, noise exposure, noise ＋ hyperbaric oxygen therapy（2ATA, 10 days） groups. HBOT was given immediately, and at 7 and 14 days after noise exposure. The rest five guinea pigs were randomly selected as specimen donors immediately after noise exposure. Impulse noise（peak sound pressure 142 d B SPL, pulse width 0.25 ms） was given at 100 pulses in succession. Auditory brainstem responses（ABRs） were measured before and immediately after exposure, and repeated after two, six and ten sessions of hyperbaric oxygen therapy. At the end of HBOT, changes in cochlear metabolism were measured by levels of inflammatory cytokines and oxygen free radicals. Results Compared with the noise exposure group, hyperbaric oxygen therapy immediately after noise exposure led to reduced ABR threshold shifts at 16 k Hz（P〈0.05）. Thresholds of click ABRs and tone bursts ABRs at 4, 8, and 16 k Hz were better in the hyperbaric oxygen therapy group on Day 7（P〈0.05） than those in the noise exposure only group. There was no significant difference at all tested frequencies between the noise exposure and the hyperbaric oxygen therapy groups on Day 14 day, with click and 4 k Hz tone burst ABR thresholds in the hyperbaric oxygen therapy group being somewhat worse than those in the noise exposure group. Levels of 8-OHd G, TNF-α and IL-1β in the hyperbaric oxygen treated group were lower than those in the noise only group（P〈0.05）. The level of HIF-1α in noise ＋ hyperbaric oxygen treated group was also lower than that in the noise exposure group, but showing no statistical significance.Conclusion HBOT has a significant effect in treating noise-induced hearing loss, showing its best effects on Day 7 following exposure to noise. Its effects are not only poor on Day14 after exposure to noise, but show signs of adverse effects.