乙酰半胱氨酸在豚鼠放疗后耳蜗损伤中的防护作用  

Protective effects of n-acetylcysteine on cochlear damage occuring in guinea pigs exposed to irradiation

作　　者：谢利红[1] 唐安洲[1] 尹时华[1] 谭颂华[1] 

机构地区：[1]广西医科大学第一附属医院耳鼻喉头颈外科,南宁530021

出　　处：《中华医学杂志》2012年第14期989-992,共4页National Medical Journal of China

基　　金：广西自然科学基金（桂科自0832126）

摘　　要：目的探讨乙酰半胱氨酸（NAC）在豚鼠放疗后耳蜗损伤中的防护作用。方法普通级白化豚鼠72只，随机数字表法分为4组，每组18只，分为正常组、单纯放疗组、放疗生理盐水组及NAC药物组。除正常组外，其余3组豚鼠一侧耳颞部（右耳）做一次性^60Co照射70Gy，放疗生理盐水组及NAC药物组于放疗后3h内经圆窗膜分别给予生理盐水和NAC。放疗后14d处死动物后分别做耳蜗中轴切片半胱氨酸天冬氨酸蛋白酶（Caspase）3免疫组织化学染色、Tunel染色、基底膜扫描电镜以及耳蜗丙二醛（MDA）和超氧化物歧化酶（SOD）检测。结果与单纯放疗组比较，NAC药物组：外毛细胞纤毛无明显缺失，螺旋神经节细胞（SGC）的凋亡数减少。NAC药物组耳蜗MDA含量（0．33±0．05）低于单纯放疗组（0．84±0．13）、NAC药物组SOD活力（10．7±3．0）高于单纯放疗组（8．7±1．3），差异均有统计学意义（均P〈0．05）；NAC药物组Caspase3平均光密度值（0．08±0．02）低于单纯放疗组（0．10±0．01），差异有统计学意义（P〈0．01）。NAC药物组SGC凋亡比率（7．8％±1．8％）较单纯放疗组（32．0％±8．7％）低。结论MDA水平的升高与SOD活力下降可能与耳蜗细胞的损伤有关，NAC可保护豚鼠因放疗引起的耳蜗细胞损伤。Objective To explore the protective effects of N-acetylcysteine （NAC） on cochlear damage occurring in irradiated guinea pigs. Methods Seventy-two guinea pigs were randomly divided into d groups （n = 18 each）. Control group received neither NAC nor irradiation, irradiation group received total cranium irradiation of 70 Gy, irradiation ＆ saline group cranium irradiation of 70 Gy and saline solution through a round window and NAC group cranium irradiation of 70 Gy and NAC through a round window. The right ear received radiation. The animals were sacrificed at Day 14 post-irradiation. The specimens were dehydrated, embeded in paraffin and serially cut into 5-μm slices. Sections were stained with immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling （TUNEL）. The cochlear basal membranes were observed for malondialdehyde （MDA） and superoxide dismutase （SOD） with scanning electron microscope. Results The cilium of hair cells had no clear loss and apoptotic number of spiral ganglion ceils decreased in NAC group. The average optical density value of Caspase 3 in spiral ganglion in NAC group significantly decreased versus the irradiation group （0.08±0.02 vs 0.10±0.01, P 〈0.01 ）. The level of MDA of NAC group also decreased versus the irradiation group （0.33±0.05 vs 0.84 ±0. 13, P 〈0.05）. The level of SOD in the NAC group increased versus the irradiation group （ 10.7 ±3.0 vs 8.7± 1.3, P 〈 0.05 ）. The ratio of apoptotic cell in SGC in the NAC group at Day 14（7.8% ± 1.8% ） decreased versus the irradiation group（32.0% ±8.7% ） at Day 14. Conclusion MDA and SOD may be involved in the pathogenesis of cochlear cell damage. And NAC protects the irradiated cochlear cell.

关 键 词：乙酰半胱氨酸 耳蜗 放疗 活性氧 

分 类 号：R739.91[医药卫生—肿瘤]