红景天拮抗脉冲噪声所致豚鼠听力损伤的实验研究

Experimental study on antagonistic effect of rhodiola on noise induced hearing loss in guinea pigs

目的探讨红景天对噪声所致豚鼠听力损伤的拮抗作用。方法将40只豚鼠随机分为四组,每组10只。第1组(实验对照组),噪声暴露前3天给予安慰剂淀粉片处理;第2组(实验组),噪声暴露前3天给予诺迪康胶囊处理,第1组和第2组同时暴露在相同条件的脉冲噪声中;第3组(红景天组),只给予3天诺迪康胶囊预处理,不做其他处理;第4组(生理盐水组),只给予3天生理盐水预处理,不做其他处理。采用听性脑干反应(ABR)、扫描电镜、酶联免疫吸附测定(ELISA)法比较4个组豚鼠实验前后听阈变化、观察耳蜗毛细胞纤毛变化情况及检测耳蜗中半胱天冬酶-3(caspase-3)、缺氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)和4-羟基壬稀酸(4-hydroxynonenal,4-HNE)表达情况。结果实验前4个组豚鼠听阈比较差异无统计学意义(P>0.05)。实验后24小时,第1组与第2组豚鼠听阈比较差异有统计学意义(t=21.675,P<0.05),第3组和第4组豚鼠听阈比较差异无统计学意义(P>0.05)。实验前后第1组和第2组听阈相差20 dB,差异有统计学意义(t第1组=-39.000,t第2组=-24.187,P均<0.05)。第1组高倍镜下见耳蜗外毛细胞纤毛大片缺失,第2组发现外毛细胞纤毛呈个别、散在缺失,第3组和第4组外毛细胞纤毛未见明显损伤;4个组豚鼠内毛细胞纤毛均未见缺失。4个组间caspase-3、HIF-1α和4-HNE表达比较,差异有统计学意义(F=24.674、90.258和51.663,P均<0.05);第1组和第2组caspase-3、HIF-1α和4-HNE表达显著高于第3组和第4组,差异有统计学意义(caspase-3:t第1、3组=6.624,t第1、4组=6.685,t第2、3组=4.658,t第2、4组=4.844;HIF-1α:t第1、3组=14.697,t第1、4组=11.895,t第2、3组=7.060,t第2、4组=4.938;4-HNE:t第1、3组=9.188,t第1、4组=11.261,t第2、3组=4.974,t第2、4组=6.484,P均<0.05),且第1组的caspase-3、HIF-1α和4-HNE表达较第2组升高,差异有统计学意义(tcaspase-3=2.607,tHIF-1α=7.598,t4-HNE=4.433,P均<0.05)。结论红景天能显著降低脉冲噪声暴露后ABR听阈,降低耳蜗中caspase-3、HIF-1α和4-HNE浓度,减轻耳蜗外毛细胞纤毛缺失,从而减轻听力损伤。

OBJECTIVE To investigate the antagonistic effect of Rhodiola on noise induced hearing loss(NIHL)in guinea pigs.METHODS Forty guinea pigs were randomly divided into four groups,10 guinea pigs in each group:Group 1(experimental control group),treated with placebo pill(starch slices)for 3 days before noise exposure;Group 2(experimental group),treated with Nuodikang Capsule for 3 days before noise exposure,guinea pigs in Group 1 and Group 2 was exposed to impulse noise with the same condition simultaneously;Group 3(rhodiola group),only pretreated with Nuodikang Capsule for 3 days,without any other treatment and Group 4(saline group),only pretreated with normal saline for 3 days,without any other treatment.Auditory brainstem response(ABR)threshold,scanning electron microscopy and enzyme-linked immunosorbent assay(ELISA)were measured in the cochlea of all guinea pigs to observe ABR threshold before and after the experiment respectively.The cilium of hair cells was observed and the expression of hypoxia-inducible factor-1α(HIF-1α),caspase-3 and 4-hydroxynonenal(4-HNE)was detected.RESULTS There was no significant difference in ABR threshold among Group 1,Group 2,Group 3 and Group 4(P>0.05)before the experiment.Twenty-four hours after the experiment,there was significant difference in ABR threshold between Group 1 and Group 2(t=21.675,P<0.05),20 dB of ABR threshold shift between Group 1 and Group 2 after the experiment with significant difference(tgroup1=-39.000,tgroup2=-24.187,P<0.05).There were large area deletions in cilium of outer hair cells in the cochlea observed by high power microscope.In Group 2,the cilium of outer hair cells were damaged individually and scattered,there was no obvious damage in Group 3 and Group 4,and no cilium loss of inner hair cells were observed in four groups.There were significantly different in the expression of caspase-3,HIF-1αand 4-HNE respectively(F=24.674,P<0.05;F=90.258,P<0.05;F=51.663,P<0.05)among four groups,and the expression of caspase-3,HIF-1αand 4-HNE in Group 1 and Group 2 were significantly higher than that of Group 3 and Group 4(caspase-3:tGroup1,3=6.624,tGroup1,4=6.685,tGroup2,3=4.658,tGroup2,4=4.844.HIF-1α:tGroup1,3=14.697,tGroup1,4=11.895,tGroup2,3=7.060,tGroup2,4=4.938.4-HNE:tGroup1,3=9.188,tGroup1,4=11.261,tGroup2,3=4.974,tGroup2,4=6.484,P<0.05),and the expression of caspase-3,HIF-1αand 4-HNE in Group 1 was higher than that of group 2(tcaspase-3=2.607,tHIF-1α=7.598,t4-HNE=4.433,P<0.05).CONCLUSION Rhodiola can significantly reduce the ABR threshold after exposure to impulse noise.It can also reduce the expression of caspase-3,HIF-1αand 4-HNE in the cochlea and decrease the loss of cochlear outer hair cell cilium so that Rhodiola may have protective effect after the noise damage.