放疗对耳蜗组织结构及脂质过氧化产物/抗氧化酶的影响

Effect of irradiation on the damage of cochlear and lipid peroxidation/antioxidant enzyme

目的探讨放疗后感音神经性耳聋的发生机制。方法将白化豚鼠94只随机分为观察组66只和对照组6只,观察组采用一次性70 Gy 60Co照射(右耳),于放疗后1、4、7、14、30 d各处死10只。对照组未进行放疗。取耳蜗中轴制作切片,HE染色观察结构变化,检测丙二醛(MDA)水平及超氧化物酶(SOD)活性;上述时间点分别取2只耳蜗基底膜行电镜扫描。结果放疗后观察组耳蜗出现不同程度损伤,观察组耳蜗MDA水平明显高于、SOD活性明显低于对照组,P均<0.01。结论放疗引起的耳蜗细胞损伤及MDA升高、SOD下降,此为感音神经性耳聋的发生机制。

Objective To explore the mechanism of sensorineural hearing loss after irradiation. Methods Sixty-six guinea pigs were randomly divided into observed group（60 guinea pigs） and control group（6 guinea pigs）. The right ears of observed group were given irradiation, 10 guinea pigs were sacrificed at I, 4, 7, 14 and 30 days after irradiation. The control group was given no irradiation. The specimens were dehydrated, embeded in paraffin and serially cutted. Sections were stained with haematoxylin and eosin for light microscopic examination, and the level of malondialdehyde （MDA） and activity of supperoxide dismutase （SOD） were examined. Results Inner ear damage was found in the observed group after irradiation, the level of MDA in observed group was significantly higher than that in control group, but the activity of SOD was significantly lower than that in control group. Conclusions Irradiation might cause cochlear cell damage, increse of MDA and decrease of SOD; this may be the mechanism of sensorineural hearing loss.