目的 探讨60CO照射后豚鼠听损伤及与耳蜗螺旋神经节细胞(spiral ganglion cell,SGC) Caspase3、Caspase8、Caspase9表达的关系.方法 选择白化豚鼠40只,随机分为对照组和放射组.对照组8只不实施60CO 照射行ABR检查后处死；放射组32只豚鼠右耳耳颞部一次性给予60CO 70Gy照射,于照射后第1、4、7、14天行ABR检查后,每个时间点各处死8只豚鼠,行耳蜗中轴切片HE染色及免疫组织化学染色,观察SGC形态变化及Caspase3、Caspase8、Caspase9的表达.结果HE染色显示放射组SGC出现萎缩改变,照射后第4、7、14天ABR反应阈分别为25.0±11.72、47.5±11.90、55.00±7.07 dB nHL,与对照组(11.66±2.58 dB nHL)比较差异有统计学意义(P＜0.05或P＜0.01).放射组SGC的Caspase 3、Caspase8、Caspase 9的阳性表达比对照组强,照射后第1、4、7、14天SGC的Caspase3平均光密度值分别为0.10±0.02、0.11±0.02、0.14±0.01、0.10±0.01,与对照组(0.07±0.01)比较差异均有统计学意义(P＜0.05或P＜0.01).照射后第1天(0.12±0.01)、4天(0.23±0.04)、7天(0.11±0.01)、14天(0.21±0.03)SGC的Caspase8平均光密度值与对照组(0.05±0.02)比较差异均有显著统计学意义(P＜0.01).照射后第4、7、14天SGC的Caspase9平均光密度值分别为0.22±0.03、0.35±0.02、0.29±0.02,与对照组(0.12±0.01)比较差异均有显著统计学意义(P＜0.01).结论 60C0照射导致豚鼠的听损伤可能与耳蜗SGC的萎缩有关,SGC的萎缩可能与Caspase 3、Caspase8、Caspase 9在SGC的表达上调有关.%Objective To explore the hearing damage and caspase expression in spiral ganglion cells in inner ear in guniea pigs after 60CO irradiation. Methods Forty guinea pigs were randomly divided into control group and irradiational group. The control group received no irradiation and was sacrificed after ABR inspection. The right ear was the radiation ear in irradiational group. The guinea pigs were sacrificed at 1,4 ,7 and 14 days after 60CO irradiation of 70 Gy. All specimens were dehydrated) embeded in paraffin and serially cutted into slices. Sections were stained with haematoxylin and eosin and immunohistochemistry for light microscopic examination. Results In irra-diatiolal group,the ABR threshold significantly increased at 4 days(25±ll. 72 dB nHL),7 days(47. 5±11. 90 dB nHDand 14 days(55. 00±7. 07 dB nHL) after irradiation compared with the control group(ll. 66±2. 58 dB nHL). It was observed that irradiation group promoted degeneration in spiral ganglion cells at these time points. The average optical density value of caspase3 increased at 1 days(0. 10±0. 02) ,4 days(0. ll±0. 02) ,7 days(0. 14±0. 01) ,14days(0.10±0.10)compared with that of the control group(O. 07±0. 01). There was a singnificantly difference on irradiation-induced average optical density value of caspase8 in spiral ganglion in lday(0. 12±0. 01),4 days(0. 23± 0.04),7 days(0. 11 + 0.01),14 days(0. 21±0. 03) versus controll group(0. 05±0. 02). There was a singnificantly difference on radiation-induced average optical density value of caspase9 in spiral ganglion at 4 days(0. 22±0. 03), 7 days(0. 35±0. 02), 14 days(0. 29±O. 02) versus controll group(0. 12±0. 01). Conclusion Irradiation might cause spiral ganglion cell damage. Caspase3, caspase8 and caspase9 cascade might be involved in the course of SGC damage.
展开▼
