Department of Otolaryngology Head and Neck surgery, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai 200433, PR China.
Neuroscience. 2012 May 3;209:47-53. doi: 10.1016/j.neuroscience.2012.02.028. Epub 2012 Feb 22.
To examine the efficiency of hydrogen-rich saline in the treatment of intensive noise-induced cochlear injury.
Forty guinea pigs were assigned to one of four groups: HS+NOISE (i.p. injection hydrogen-rich saline), NS+NOISE (i.p. injection normal saline), NOISE ALONE (noise control), and NO TREATMENT (normal control) groups. The HS+NOISE, NS+NOISE, and NOISE ALONE groups were exposed to intensive noise (4 h at 115 dB SPL noise of 4000±100 Hz). The auditory brainstem response (ABR) was used to examine the hearing threshold in each group. Distortion product otoacoustic emission (DPOAE) was used to examine outer hair cell function. We also examined cochlear morphology to evaluate inner and outer hair cell trauma induced by noise exposure. Hydrogen-rich saline was administered twice daily for 6 days (2.5 ml/kg, i.p.) 24 h after noise exposure.
Baseline ABR thresholds and DPOAE values were normal in all groups at the measured frequencies (2, 4, 8, and 16 kHz) before noise exposure. The ABR threshold shift was 50-55 dB across the frequencies tested, and average DPOAE declined in the NOISE ALONE, NS+NOISE, and HS+NOISE groups 24 h after noise exposure. However, the changes in cochlear parameters were different between groups. The HS+NOISE group showed a significantly decreased ABR threshold value as compared with the NS+NOISE or NOISE ALONE group (P<0.01) on day 7. The mean DPOAE recovered to some extent in the three noise exposure groups, but at most frequencies the HS+NOISE group showed significantly increased DPOAE on day 7 as compared with the NS+NOISE group or NOISE ALONE group (P<0.01). Surface Corti organ preparations stained with succinate dehydrogenase (SDH) showed that most outer hair cells (OHCs) were still dropsical and a few were missing 7 days after noise exposure in the NS+NOISE group. Only a few OHCs were slightly dropsical in the HS+NOISE group. The numbers of missing hair cells 7 days after noise exposure were significantly greater in the NOISE ONLY and NS+NOISE groups than the HS+NOISE group (P<0.01).
Hydrogen-rich saline can alleviate experimental noise-induced hearing loss in guinea pigs, partially by preventing the death of cochlear hair cells after intensive noise exposure.
研究富氢生理盐水治疗强噪声诱导耳蜗损伤的疗效。
40 只豚鼠随机分为 HS+NOISE（腹腔注射富氢生理盐水）、NS+NOISE（腹腔注射生理盐水）、噪声暴露组（NOISE ALONE）和正常对照组（NO TREATMENT）。HS+NOISE、NS+NOISE 和 NOISE ALONE 组暴露于 115dB SPL（4000±100Hz）噪声中 4 小时。采用听性脑干反应（ABR）检测各组听力阈。采用畸变产物耳声发射（DPOAE）检测外毛细胞功能。观察耳蜗形态，评估噪声暴露引起的内外毛细胞损伤。噪声暴露后 24 小时，腹腔注射富氢生理盐水 6 天（2.5ml/kg，2 次/天）。
噪声暴露前，各实验组在测试频率（2、4、8、16kHz）的基础 ABR 阈值和 DPOAE 值均正常。ABR 阈值在所有频率均增加 50-55dB，NOISE ALONE、NS+NOISE 和 HS+NOISE 组噪声暴露后 24 小时 DPOAE 均值降低。然而，各组耳蜗参数的变化不同。与 NS+NOISE 组或 NOISE ALONE 组相比，HS+NOISE 组噪声暴露后第 7 天 ABR 阈值明显降低（P<0.01）。三组噪声暴露后 DPOAE 均值在一定程度上恢复，但与 NS+NOISE 组或 NOISE ALONE 组相比，HS+NOISE 组在大多数频率上 DPOAE 均值在第 7 天明显升高（P<0.01）。SDH 染色的表面 Corti 器官显示，NS+NOISE 组在噪声暴露后第 7 天，大部分外毛细胞（OHCs）仍水肿，少数缺失。HS+NOISE 组仅有少数 OHC 轻度水肿。NOISE ONLY 和 NS+NOISE 组噪声暴露后第 7 天缺失的毛细胞数量明显多于 HS+NOISE 组（P<0.01）。
富氢生理盐水可减轻豚鼠实验性噪声性听力损失，部分机制可能是防止强噪声暴露后耳蜗毛细胞死亡。
