高频连续噪声对豚鼠听阈及耳蜗结构的影响

目的研究高频连续噪声暴露对豚鼠听阈及耳蜗结构的影响。方法16只雄性花色豚鼠随机分为噪声暴露组和对照组,每组8只豚鼠。噪声暴露组豚鼠于噪声暴露前测定听觉脑干反应阈值(auditorybrainstem responses,ABR),每日接触中心频率为4 kHz、倍频程、100 dB(A)声压级(sound pressure level,SPL)连续噪声,每天8 h,连续7 d;末次噪声暴露结束后第8天,测定ABR后处死豚鼠,取耳蜗,进行组织病理学、透射电镜及扫描电镜的观察。对照组豚鼠不接触噪声,于相应时间点测定ABR,其他处理同噪声暴露组。结果噪声暴露组豚鼠在2,4,8 kHz处的阈移分别为13.4,31.3,31.9,耳蜗外毛细胞静纤毛发生散在缺失、倒伏,胞浆萎缩、空化,细胞核萎缩或消失,部分线粒体消失,个别线粒体发生髓样变。结论噪声暴露可提高豚鼠的听阈并对其耳蜗结构具有损伤作用。     

噪声习服对听力损伤保护作用的时程研究

目的观察噪声习服对豚鼠听力损伤防护效应的时程变化。方法20只雄性豚鼠随机分为噪声习服组（A组）和直接暴露组（B组）。A组动物在声压级为90 dB SPL（声压级）、中心频率为0.5 kHz的一个倍频程噪声下连续暴露10 d,每天6 h,休息5 d,然后与B组动物同时在105 dB的白噪声下连续暴露7 d,每天4 h。每天在强噪声暴露前、后测定两组动物的听觉脑干反应（ABRs）阈值。结果A组动物在接受低噪声暴露后产生了习服效应。强噪声暴露后,A组1-7 d的平均阈移逐渐增加,而B组的平均阈移则逐渐减少;除第7天时的6 kHz频率外,A组在各时点上的click和短纯音（4、6、8 kHz）的平均阈移均显著低于B组。结论噪声习服对强噪声暴露引起的听力损伤具有一定的保护作用,但随着时间的推移,这种作用逐渐减弱。     

维生素C对豚鼠噪声性听力损失的预防作用

目的 研究维生素C对噪声性听力损失是否具有预防作用。方法 40只雄性花色豚鼠随机分为5组，每组8只。其中3组接受噪声暴露，分别腹腔注射生理盐水、维生素C(10．0，50．0mg／kg)；另2组无噪声暴露，分别腹腔注射生理盐水、维生素C(50．0mg／kg)。比较噪声暴露后各组豚鼠听觉脑干反应(ABR)的阈移，评价维生素C对噪声性听力损失的预防作用。结果腹腔注射10．0，50．0mg／kg维生素C可在一定程度上减少噪声对豚鼠引起的ABR阈值增高。结论 维生素C具有一定的预防噪声性听力损失的作用。     

噪声对豚鼠耳蜗抗氧化酶防御体系的影响

目的　了解噪声对耳蜗抗氧化酶防御体系的影响。方法　雄性花色豚鼠 1 6只 ,体重2 50～ 30 0g,随机分为 2组 ,正常对照组和噪声暴露组 ,每组 8只。噪声暴露组接触中心频率为 4kHz的倍频程连续噪声 ,强度为 1 0 0dB(SPL) ,每天 8h ,连续 3d。于接触噪声前、噪声暴露结束后即刻测定听觉诱发脑干反应 (ABR) ,并测定活性氧 (ROS)水平和超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GSH Px)活力。结果　噪声暴露组的ROS水平为 (2 81 .2± 3 .5)U/mgpro ,正常对照组为 (2 73 .0± 3 .2 )U/mgpro,差异有显著性 (P <0 .0 5) ,SOD、CAT及GSH Px活力分别为 (2 0 6 .5±5 .1 )NU/mgpro、(47.0± 9.0 )U/gpro、(1 4 .1± 2 .5)U/mgpro,比正常对照组 [分别为 (2 2 1 .8± 4 .8)NU/mgpro、(60 .8± 9.9)U/gpro、(2 1 .1± 3 .1 )U/mgpro]明显降低 ,且差异有显著性 (P <0 .0 5)。结论　噪声可以损伤耳蜗的抗氧化酶防御体系     

工业噪声性听力损失动物模型的构建与应用

目的构建工业噪声性听力损失动物模型。方法将50只雄性豚鼠随机分为5组,除对照组外其余4组分别予以85 dB(SPL)、95 dB(SPL)、105 dB(SPL)和115 dB(SPL)的模拟稳态工业噪声暴露28 d(6 h/d),于暴露前及暴露后7 d分别进行听性脑干反应(ABR)检测,以评价各组豚鼠噪声暴露后的听阈位移水平,暴露后取豚鼠耳蜗观察毛细胞的病理学变化。结果对照组及各噪声暴露组豚鼠听阈位移水平变化均表现出明显不同,平均听阈位移水平对照组为0.00 dB、85 dB(SPL)暴露组为6.75 dB、95 dB(SPL)暴露组为13.25 dB、105 dB(SPL)暴露组为21.50 dB、115 dB(SPL)暴露组为28.00 dB,听阈位移水平变化随着噪声暴露强度的增强而增加,不同组间差别有统计学意义(F=319.995,P=0.00);病理学观察发现耳蜗毛细胞结构随着噪声暴露强度的增加而损伤程度加重。结论模拟工业噪声性听力损失的豚鼠模型构建成功,它将为职业噪声性听力损失的发生机制及干预提供良好的研究平台。 更多还原     

亚氨乙基赖氨酸拮抗噪声损伤豚鼠听力的实验研究

目的　探讨亚氨乙基赖氨酸对豚鼠噪声性损伤的拮抗作用。方法　选健康白色红目豚鼠 4 0只 ,随机分为 4组 :A组为正常对照组 ,B组为噪声组 ,C组为噪声 +药物组 ,D组为亚氨乙基赖氨酸组。B、C组豚鼠暴露于 115dB白噪声连续 6d ,每天连续 6h ;C组豚鼠每天腹腔注射亚氨乙基赖氨酸 10mg/kg ,B组豚鼠腹腔注射等量的生理盐水 ,D组豚鼠每天腹腔注射亚氨乙基赖氨酸 10mg/kg,并不暴露于噪声。各组豚鼠在实验前、后均行ABR听阈检测。用免疫组化方法检测诱生型一氧化氮合成酶 (NOSⅡ )在各组豚鼠耳蜗的表达。各组豚鼠耳蜗行扫描电镜检查。观察比较各组豚鼠ABR听阈、NOSⅡ染色强弱及耳蜗形态。结果　实验前 ,A、B、C、D各组间ABR听阈的差异无显著性 (P >0 .0 5 )。实验后 ,A组、D组ABR听阈无明显改变 ,而B组和C组ABR听阈则有明显改变 ,B组ABR听阈为 (6 0 .2 3± 11.2 3)dB ,C组为 (38.4 6± 7.2 4 )dB ,两组比较 ,差异有显著性 (P <0 .0 5 )。NOSⅡ在A、D组耳蜗表达阴性 ,B组耳蜗表达较强 ,C组耳蜗表达较弱。B组豚鼠耳蜗外毛细胞损伤较C组重。结论　NOSⅡ在噪声所致豚鼠耳蜗损伤中呈阳性表达 ,亚氨乙基赖氨酸能抑制NOSⅡ的活力 ,且对噪声所致豚鼠耳蜗损伤有拮抗作用 ,表明一氧化氮在噪声性聋的发病中起重要作用。     

噪声习服对人体听觉系统保护作用

目的 探讨噪声习服对人体听觉系统的保护作用及其抗脂质过氧化机制.方法 适应组每天4 h低强度噪声的习服性暴露,连续6 d,结束后,休息2 d,然后每天3 h高强度噪声暴露,连续6 d;对照组,每天3 h的高强度噪声暴露,连续6 d.测量2组高强度噪声暴露后的暂时性阈移(TTS),及血液中丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)的含量.结果 适应组高强度噪声暴露后的TTS明显小于对照组(0.4～4 kHz,平均差异6.7 dB,P≤0.05);血清MDA 下降、SOD上升、全血GSH上升.结论 噪声习服可降低TTS,减轻脂质过氧化反应对听力的损伤,提示应用自由基清除剂和抗氧化剂可能预防或减轻噪声引起的听力损伤.     

听性脑干反应消失婴幼儿的多频稳态诱发电位测试

目的:通过多频稳态诱发电位(ASSR)测试技术,了解婴幼儿残余听力情况,为早期诊断、早期干预提供依据。方法:将受试对象分为2组即对照组和异常组。对照组40例(80耳)为听力正常婴幼儿;异常组60例(120耳)为听性脑干反应(ABR)消失婴幼儿。2组分别进行声导抗测试、ABR、ASSR检测。对比观察不同组别间ABR、ASSR引出率及反应阈值。结果:①对照组ASSR在0·5、1·0、2·0和4·0kHz点引出率为100%,反应阈分别为21·0±9·73、23·5±7·25、20·15±7·5、17·65±7·78,ABR反应阈为24·0±6·53。②异常组ASSR在0·5、1·0、2·0和4·0kHz点引出率分别为55·8%、68·3%、46·7%、25·0%,反应阈分别为88·4±9·9、99·1±9·9、100·7±8·5、98·8±6·5。结论:ABR测试具有快速、无创、客观等优点,为较好地婴幼儿听功能检查方法,但其频率特性差、输出强度小,难以真实地反映极重度婴幼儿的残余听力情况,ASSR有较好频率特性,对极重度聋婴幼儿是否有残余听力存在有较好诊断价值,是婴幼儿听力损失定量诊断方法。     

机场机坪地勤人员噪声暴露的测量与评价

目的　对机场机坪地勤人员的噪声暴露进行测量和评价。方法　根据工作性质和内容 ,将某机坪区域及机库工作的地勤人员分为 1 0个组 ,每组选取 3～ 9人作为个体噪声暴露测量的对象。工作前将话筒固定在衣领上 ,SH - 1 2 6记录式声级计由地勤人员随身携带 ,仪器自动记录工作期间的噪声暴露数据 ,工作结束后将数据转入计算机 ,用软件计算等效声级。结果　工作期间地勤人员的个体噪声暴露水平不稳定 ,用个体计量仪可以记录和分析地勤人员工作期间噪声暴露水平的动态变化和等效声级。 4个飞机航线及 1个机库检修组日班的平均噪声暴露为 85 0～ 94 8dB (A) ,夜班为 77 6～ 84 9dB (A) ,其余工种的噪声暴露分别为金工 [(98 8± 3 9)db(A) ]>特种车辆司机 [日班 (93 5± 9 5 )db(A) ,夜班 (84 7± 5 4 )dB(A) ]>飞机协调员 [日班 (87 3± 3 7)dB(A) ,夜班 (85 5± 4 1 )dB(A) ]>文件准备 [(80 7± 4 4 )dB(A) ]>地毯清洁 [(79 0± 3 8)dB(A) ]。结论　地勤人员接触不稳定噪声。该机场绝大多数地勤人员的噪声暴露水平超过85dB(A) ,应纳入机场职工的听力保护计划。     

鼓膜穿孔对噪声性听损伤豚鼠听功能的影响

[目的]观察鼓膜穿孔对噪声性听损伤的豚鼠脑干诱发电位和畸变产物耳声发射的影响。[方法]10只豚鼠分别行右鼓膜穿孔,穿孔面积约占整个鼓膜的25%,左耳为对照耳。每天定时暴露于稳态噪声4h,连续暴露6d,观察左右两耳听觉脑干诱发电位(auditory brainstem response,ABR)和畸变产物耳声发射(distort product otoacoustic e-mission,DPOAE)的变化。[结果]两耳均出现ABR反应阈的上升和DPOAE幅值下降,脱离噪声暴露一段时间后,正常耳可恢复,穿孔耳仍有听阈的暂时性阈移,二者差异有统计学意义。[结论]鼓膜穿孔后,耳蜗外毛细胞对噪声更敏感,听阈的暂时性阈移恢复延迟。     

Uniform comparison of several drugs which provide protection from noise induced hearing loss

Background  

The ability of drugs to reduce noise induced hearing loss (NIHL) has been evaluated in diverse experimental conditions (animal species, noise intensities, durations, assessment techniques, etc), making it difficult to assess their relative efficacy. The present study was designed to provide more uniform comparisons and to allow to a better understanding of the mechanism of the NIHL. Methods: The drugs studied included furosemide (loop diuretic) and the antioxidants N Acetyl-L-Cysteine, vitamins A, C, E with the vasodilator magnesium. Mice were exposed to a continuous broadband noise (113 dB SPL for 3.5 hours) and the NIHL was assessed in all animals before noise exposure and 1 week after with auditory nerve brainstem evoked responses (ABR) to broadband clicks and to 8 kHz tone bursts.     

葡萄糖摄入与间歇暴露对噪声性听力损伤的防护作用

This paper reports the way which protects hearing from harmful effects of noise. 67 guinea pigs were divided into four groups, 8-9 guinea pigs in each group. The total time of noise exposure at 125 dB SPL white noise in each group was one hour. The control was exposed continuously for 1 hour. Group I was exposed to noise for 30 minutes after intraperitoneal injection of glucose at 2 mg/g body wt., then rest for 30 minutes and exposed for 30 minutes again. Group II was exposed continuously to noise for 1 hour after intraperitoneal injection of glucose at 2 mg and 4 mg/g body wt. Group III was exposed to noise for 30 minutes, rested for 30 minutes and exposed for 30 minutes again without glucose injection. The auditory brain stem response (ABR) was measured before, immediately, 3 days, and 7 days after noise exposure. The effect on hearing conservation was evaluated according to ABR threshold. We observed that the auditory threshold in group I was significantly lower than that of the control in the given time after noise exposure (P less than 0.05), but not so in group II and III. Combined use of glucose and rest period between noise exposure was able to decrease the threshold shift by 15 dB and 10 dB immediately and 7 days after noise exposure respectively.     

Combined exposure to noise and vibration and its effects on workers' hearing

OBJECTIVE: To assess the exposure of bus drivers to noise and whole-body vibration (WBV) and to examine the possibility of an association between these risk factors for noise-induced hearing loss. METHODS: A cross-sectional study was carried out among 141 bus drivers who underwent an audiometry test. This group was classified and internally stratified in subgroups of "exposed" and "controls" according to cumulative working time as bus drivers. Their exposure to noise and vibration was assessed. The association between noise-induced hearing loss (NIHL) and the set of explanatory variables was analyzed through logistic regression. RESULTS: The average (+/- standard deviation) weekly noise exposure of front-engine bus drivers was 83.6 +/- 1.9 dB(A), while rear-engine bus drivers were exposed to 77.0 +/- 1.1 dB(A). The weighted average of vibration acceleration was 0.85/m(2). In the best adjusted model, the multivariable analysis showed that age (>44; OR=2.54; 95% CI=1.15-5.62), diabetes (OR=5.46; 95% CI=0.95-31.4), and the level of noise emission [>86.8 dB(A); OR=2.76; 95% CI=1.24-6.15] were risk factors for NIHL. In another model studied, WBV exposure was significant in determining NIHL. CONCLUSIONS: Bus drivers were exposed to significant WBV levels. The noise exposure was more pronounced in front engine than in rear-engine vehicles. No association between WBV exposure and NIHL was observed and no interaction was found between WBV and noise exposure. Further studies are required as other model indicated an association between WBV and NIHL.     

A seven-year review of measured hearing levels in male manual steelworkers with high initial thresholds

ABSTRACT Audiometric records of 449 male manual steelworkers were reviewed to see whether the hearing of men with high initial threshold levels deteriorated more rapidly than that of those men with more normal thresholds when exposed to similar noise levels. Subjects were between 15 and 54 years old at the time of initial examination, and had a repeat audiogram 6-8 years later. They were classified into three occupational noise exposure groups: below 90 dB(A), 90-99 dB(A), and 100 dB(A) or over, without knowledge of their audiometric threshold levels, age, or aural history. Measurements at 0·5, 1, 2, 3, 4 and 6 kHz for the right ear were considered, first as the mean for all six frequencies, then for 0·5, 1 and 2 kHz only, and finally for 6 kHz only. After standardisation for age, it was found that those in the high initial threshold groups deteriorated no faster than the remainder of the series. At the 90-99 dB(A) noise exposure level, χ² tests showed that the differences between the groups, in terms of mean measured hearing loss, were not significant at the 0·05 probability level. The age-standardised mean threshold shifts for the 0·5-6 kHz range of frequencies over the seven-year review period were 7·5, 8·7 and 7·1 dB at a noise exposure level of 100 dB(A) or more, for workers with an initial threshold level of <12 dB, 12-26 dB and > 26 dB respectively; for those exposed to noise of 90-99 dB(A) the corresponding mean shifts were 7·8, 6·8 and 7·3 dB respectively; while for those exposed to noise of less than 90 dB(A) the mean shifts were 6·2, 5·0 and 5·2 dB respectively.     

噪声暴露对大鼠短纯音与短声听觉脑干反应的影响

目的 研究噪声暴露对大鼠听觉脑干反应(ABR)的影响,及大鼠短声ABR(C-ABR)和短纯音ABR(Tb-ABR)的特点,以探讨Tb-ABR在听力评估中的价值.方法 将成年SD大鼠随机分为噪声组和正常组,每组7只(14耳).噪声组暴露于100 dB(SPL)白噪声,6 h/d,连续12周.噪声停止后24 h分别测定C-...     

Noise-induced hearing loss in rats

The effect of noise exposure on the auditory system is well known from animal studies. However, most of the studies concern short-term exposure conditions. The purpose of the present research was to find the dose-effect curve for hearing loss in rats following 5 days of noise exposure. Three groups of eight Wag/Rij rats were exposed to broad band noise at levels of 90, 100 and 110 dB SPL for 8 hours/day and 5 consecutive days. An additional group of eight rats served as the control group. Between three and seven weeks after the exposure, hearing was tested by electrocochleography (CAP) and distortion product otoacoustic emissions (DPOAE). Subsequently, the cochleas were morphologically examined. Only the highest two exposure levels affected hearing. The DPOAE growth curves at 4, 8 and 16 kHz and the CAP growth curves at 4, 8, 12, 16 and 24 kHz were affected after the 110 dB SPL broad band noise. After the 100 dB SPL noise, only the 12 kHz CAP growth curve was affected. At the light-microscopic level, OHC damage was not detected in this study.