EGCG对阿米卡星诱导大鼠螺旋神经元凋亡的保护作用

(-)EGCG suppress amikacin-induced spiral ganglion neuron apoptosis in the rat cochlea

目的探讨表没食子儿茶素没食子酸酯(EGCG)。对阿米卡星诱导的大鼠耳蜗螺旋神经元凋亡是否具有保护作用。方法设生理盐水对照组、阿米卡星(450 mg.kg-1.d-1共14 d)损伤组和阿米卡星加EGCG(50 mg/kg.kg-1.d-1共14 d)保护组。各组动物均深度麻醉后半身灌注固定处死,取右侧耳蜗标本固定、脱钙、石蜡轴位包埋、轴位切片,近中轴位切片行末端脱氧核苷酸转移酶介导的dUTP原位切口末端标记(TUNEL)免疫组化染色,光学显微镜下检测耳蜗螺旋神经节细胞表达情况、并通过切片图像分析进行半定量处理比较。结果正常组螺旋神经元胞浆及细胞核基本上均不着色,损伤组部分螺旋神经元胞核着色,保护组亦少部分螺旋神经元胞核着色,图像分析结果显示损伤组与对照组、损伤组与保护组之间的染色阳性率差异有统计学意义(P<0.01)。结论EGCG可以减轻阿米卡星诱导大鼠耳蜗螺旋神经元凋亡。

Objective To study the effects of （-）-epigallocatechin-3-gallate （EGCG） on amikacin-induced spiral ganglions neurons apoptosis in the rat cochlea. Methods All animals were divided into three groups：one group serving as the saline control group,one group receiving amikacin（Amk） at 450 mg/kg once a day for 14 days,one group receiving Amk plus EGCG at 50 mg/kg once a day for 14 days. Following deep anesthesia, the animals were half-body perfused intracardially with 4% paraformaldehyde （PFD）, and the buUas were harvested, and fixed in PFD ,and decalcified in ethylenediamine tetraacetic acid（ EDTA ）. After decalcification ,the cochlea were embedded in paraffin, and cut in a paramodiolar plane subsequendy. The immunohistochemical changes were observed for detecting with terminal deoxynucleotidyl transferase（TdT） dUTP nick end labeling （TUNEL）. Results The negative immunohistochemical reaction for TUNEL staining was found in the spiral ganglion neurons（SGNs） in the saline control grou-p;and the positive reaction was found in the nucleolus of the part of the SGNs of the group receiving Amk. However,the positive staining could be detected hardly in the group receiving Amk plus EGCG. The image analysis showed that the percentage of the positive SGNs in the group receiving Amk was significantly higher than that in the control group,and the percentage of the positive SGNs in the group receiving Amk plus EGCG was significantly lower than that in the group receiving Amk （ P 〈 0. 01 ）. Conclusions Tunel-staining demonstrated Amk-indueed SGNs apoptosis in the rat cochlea. EGCG effectively suppressed amikacin-induced spiral ganglion neuron apoptosis.