60Coγ射线照射对豚鼠耳蜗功能和结构的影响

本实验采用模拟临床放射治疗常规分割照射方法，对豚鼠内耳进行６０Ｃｏγ射线外照射，研究电离辐射对耳蜗功能和结构的影响，以探讨临床上头颈部恶性肿瘤患者放射治疗后听力减退的原因和预防措施．研究发现，照射后１０周，豚鼠听觉脑干反应（ＡＢＲ）听阈随着照射剂量的提高而相应上升，７０Ｇｙ组平均上升１０ｄＢ，９０Ｇｙ组平均上升２８ｄＢ；耳蜗基底膜铺片检查发现，照射剂量与外毛细胞、内毛细胞和柱状细胞缺失数量呈正相关；损伤严重程度：外毛细胞＞内毛细胞＞柱状细胞；统计分析组间Ｐ＜０．０５．本研究提示，γ射线对耳蜗毛细胞的破坏损伤，是听觉下降主要原因．

Effect of 60Co gamma irradiation on cochlear function and structure in guinea pigs

In the experiment inner ears ofguinea pigs were irradiated with60Co gamma rays using the methodof simulated clinical routine irradiation in order to find the effects of ionizing radiation on thecochlear fonction and structure,and explore the mechanism and protective measure that lead to hearingimpairment following radiotherapyto the head and neck of cancer patients .Ten weeks after irradiationit was found that ABR thresholdincreased with increasing dose ofradiation' The mean values of ABRthresholds in 70 Gy and 90 Gy groupswere 10 dB and 28 dB respectively.The number of inner and outer haircell and pillar cell loss was countedunder microscope. The numberof lost cells increased with increasingdose of radiation. The severity ofdamage in morphology of inner,outerhair cells and pillar cells reducedprogressively. The groups of 70 Gyand 90 Gy lost significantly morethan groups of contral and 50Gy Gy(P<0. 05) .It is concluded that the damage of hair cells of cochlea is thedirect rssult of gamtna ray irradiation of the inner ear and is the maincause of hearing imparment following irradiation.