声预处理对强噪声引起听力损伤保护作用的研究(英文)

目的 探讨低频声预处理对强噪声及中频强噪声引起听力损伤的保护作用。方法 两组声预处理组豚鼠在中心频率０．５ｋＨｚ８５ｄＢ倍频带噪声作用下，连续暴露４ｄ（６ｈ／ｄ）后，在无噪声情况下恢复３ｄ。随后分别在中心频率０．５ｋＨｚ和１ｋＨｚ１１０ｄＢ的倍频带噪声下，暴露１ｈ。两组对照组豚鼠不经声预处理，分别直接暴露在中心频率０．５ＫＨｚ和１ｋＨｚ１１０ｄＢ的倍频带噪声下，暴露１ｈ。两组对照组豚鼠不经声预处理

Effects of Sound Preconditioning on Hearing Loss from Low or Middle Frequency Noise Exposure

ObjectiveTo explore prior noise exposures or sound conditioning as a moderator of hearing lossproduced by traumatic exposure to low or middle-frequency noise. Method Two experimentalgroups of guinea-pigs were conditioned using a 0.5 kHz octave band noise (OBN) at 85 dB,6h/d for 4 d.The subjects were allowed to recover for 3 d after conditioning.Then the firstgroup was exposed to a 0.5 kHz OBN at 110 dB for 1 h,the second group was exposed to 1 kHzOBN at 110 dB for 1 h.Two control groups received 0.5 kHz and 1 kHz OBN respectively at110 dB for 1 h without prior sound conditioning. Result Hearing threshold shifts recordedat 48 h after the high-level noise exposure in conditioned groups and control groupsdemonstrated that conditioning provided significant protection on hearing threshold shiftfrom low or middle frequency noise exposure.Histological examination revealedsignificantly less hair cell loss in the conditioned than in the control groups.Inaddition,malondialdehyde(MDA) levels in red blood cell(RBC) of conditioned groups weresignificantly lower as compared with that of the control groups. Conclusion Low-frequencyconditioning provided significant protection not only on hearing threshold shift caused bynoise of the same frequency,but also on that caused by middle frequency noise.