Objective To evaluate the protective effects of oral administration of D-methionine tablets on noise-induced hearing loss.Methods A total of 203 volunteers were recruited and randomly divided into two groups:experimental group (n=113)and control group (n=90).The subjects in the experimental group received oral administration of D-methionine tablets(1 500 mg/day)and those in the control group received placebo for 3 days before impulse noise exposure.The routine audiometric evaluation and ABR testing were performed and recor-ded 1 day and 7 days post- noise exposure.The statistical analysis was carried out with SPSS 11.0.ResuIts The changes of hearing in all participators were observed after noise exposure.The results were as follow:The hearing thresh-olds at three time points were 40.5±9.3,51.7±12.3,44.1±11.4 dB nHL in experimental group and 41.5±8.9,62.4± 13.7,47.6±12.5 dB nHL in control group,respectlvely;the ABR I-V IPLs at three time points were 3.72±0.21 ms, 3.99±0.36 ms,3.82±0.25 ms in experimental group,while 3.71±0.22 ms,4.45±0.37 ms,3.85±0.34 ms in control group,respectively.There were statistically significant differences between the two groups.ConcIusion The oral adminis-tration of D-methionine tablets pre noise exposure can protect against noise-induced hearing loss.

OBJECTIVE: To evaluate the protective effects of oral administration of D-methionine tablets on noise-induced hearing impairment. METHOD: Two hundred and three volunteers were recruited and randomly divided into two groups: experimental group (n= 113) and control group (n=90). The subjects received oral administration of D-methionine tablets in the experimental group and placebo in the control group before noise exposure. Routine audiometric evaluation and ABR testing were performed and recorded before and after noise exposure. The statistical analysis was carried out with SPSS 11.0. RESULT: There were no differences in auditory threshold and I-V interpeak latency pre-noise exposure (P>0.05), however, there were statistically significant differences between two groups 1 d, 7 d after noise exposure (P<0.01 and P<0.05). In-respective-group, there were statistically significant differences between before and 1 d after noise exposure (P<0.05 and P<0.01), however, no difference was noted between before and 7 d after noise exposure in the experimental group (P>0.05). CONCLUSION The protective effects of D-methionine tablets were prominent on the noise-induced hearing impairment. Further studies regarding the optimal time of D-methionine administration will be recommended in the future.
Administration, Oral ; Adult ; Hearing Loss, Noise-Induced ; drug therapy ; Humans ; Male ; Methionine ; therapeutic use ; Young Adult

OBJECTIVE: To evaluate the protective effects of oral administration of N-acetyl-cysteine (NAC) on noise-induced hearing loss. METHOD: Three hundred sixty three volunteers were recruited and randomly divided into two groups: experimental group (n=223) and control group (n=140). The subjects had received oral administration of NAC in the experimental group and placebo in the control group before noise exposure. The routine audiometric evaluation and ABR testing were performed and recorded pre- and post-noise exposure. The statistical analysis was carried out on the data obtained from two groups with SPSS 11.0. RESULT: The hearings of all the participatory were changed after noise exposure, but there were statistically significant differences between two groups. CONCLUSION The protective effects of NAC were prominent on the noise-induced hearing loss.
Acetylcysteine ; administration & dosage ; therapeutic use ; Adult ; Hearing Loss, Noise-Induced ; drug therapy ; prevention & control ; Humans ; Male ; Military Personnel ; Young Adult