【摘要】 目的研究噪声暴露对豚鼠耳蜗Bcl-2、Bax基因的表达及Bcl-2/Bax的影响,探讨噪声性听力损失(NIHL)的细胞凋亡机制。方法 36只SPF级健康雄性豚鼠随机分为对照组、95 d B、115 d B声压级(SPL)暴露组3组,每组12只,除对照组外分别予以95 d B、115 d B SPL的高斯白噪声暴露(28 d、6 h/d),暴露前1 d和暴露结束后d 7,分别进行听性脑干反应(ABR)测量、暴露结束后d 7进行耳蜗病理学检查和荧光实时定量逆转录-聚合酶链反应(RT-PCR)法分析耳蜗Bcl-2、Bax m RNA的相对表达水平。结果 3组间豚鼠永久性听阈位移(PTS)水平比较,差异有统计学意义(χ2=26.70,P<0.0001),95 d B、115 d B SPL组豚鼠耳蜗PTS水平分别为(12.50±2.50)、(27.50±2.50)(Md±(P75-P25));病理学显示噪声暴露组的豚鼠耳蜗毛细胞和螺旋神经节细胞出现明显损伤,高强度噪声暴露损伤程度比低强度暴露严重;Bcl-2、Bax m RNA表达水平和Bcl-2/Bax比值,在3组间均有统计学差异(χ2=20.35、22.89、23.48,P<0.0001);Bcl-2 m RNA表达水平随着噪声暴露强度的增加而下调;Bax m RNA表达水平在噪声暴露为115 d B SPL组显著上调;Bcl-2/Bax比值在95 d B和115 d B SPL两噪声暴露组中,均明显低于对照组,而且随着噪声暴露强度的增加而减少。结论 NIHL可诱导耳蜗细胞凋亡的发生,Bcl-2/Bax可作为评价耳蜗凋亡水平的指标。更多还原

【Abstract】 Objective The aim of this study was to explore the influence of noise exposure on Bcl-2 and Bax expression in the cochlears pf guinea pigs, and evaluate the effect of Bcl-2/Bax. Methods Thirty-six healthy adult SPF guinea pigs were randomly divided into the control group, 95 d B and 115 d B exposure groups, with 12 in each group. Except for the control group, the pigs were exposed to 95 d B or 115 d B white Gaussian noise for 28 days, six hours a day, respectively. The auditory brainstem response(ABR)was measured one day before the exposure and seven days after the exposure, respectively. The cochlear pathological examination and RT-PCR were performed to determine the relative expression level of Bcl-2 and Bax m RNA in cochlears seven days after the exposure. Results There was significant difference between the three groups in permanent threshold shift(PTS)(χ2=26.70,P<0.0001). The PTS levels in 95 d B and 115 d B groups were 12.50 ±2.50, 27.50 ±2.50((Md±(P75-P25)), respectively. The pathological examination showed that there were significant damages in the cochlear of pigs in exposure groups. The damages were more severe in high noise exposure group(115d B). There was significant difference in the Bcl-2, Bax m RNA expression levels, and the Bcl-2/Bax ratio between the three groups(χ2=20.35, 22.89, 23.48, P<0.0001). The Bcl-2 m RNA expression level went down along with the noise exposure strength, but the Bax m RNA expression level was up-regulated obviously in 115 d B exposure group.The Bcl-2/Bax ratios in 95 d B and 115 d B exposure group were significantly lower than that in the control group, and went down along with the noise exposure strength. Conclusion The noise induced hearing lose(NIHL) could induce apoptosis of cochlear cells and the Bcl-2/Bax ratio could serve as the index of the apoptosis level of cochlears.更多还原