| 李荧,郭广威,苏纪平.经圆窗膜给地塞米松改善放射致豚鼠 内耳损害的研究[J].中华放射医学与防护杂志,2009,29(6):590-594 |
| 经圆窗膜给地塞米松改善放射致豚鼠 内耳损害的研究 |
| Direct round window membrane application of Dexamethasone in the protection of the guinea pigs' cochlea against irradiation damage |
| 投稿时间：2008-12-23 |
| DOI：10.3760/cma.j.issn.0254-5098.2009.06.009 |
| 中文关键词: 地塞米松 圆窗膜 γ线 耳蜗 |
| 英文关键词:Dexamethasone Round window membrane γ-irradiation Cochlea |
| 基金项目:广西壮族自治区教育厅科研项目(桂教科研[2003]22号) |
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| 中文摘要: |
| 目的 探讨经圆窗膜局部应用地塞米松对放射性内耳损害的保护作用,为头颈部肿瘤放疗所致内耳损害的预防和治疗提供理论依据。方法 选取130只豚鼠随机分为4组:(1)地塞米松组(45只):对豚鼠右耳进行70 Gy60Coγ线照射后,经圆窗膜给地塞米松1次;(2)单纯照射组(45只):对豚鼠右耳进行70 Gy60Coγ线照射;(3)盐水对照组(30只):对豚鼠右耳进行70 Gy60Coγ线照射后,经圆窗膜给生理盐水1次;(4)健康对照组(10只):不做任何处理。前3组动物在实验前、照射(给药)后第3天、第2周、第2个月后,分别检测听觉脑干反应(ABR),各组动物均观察中耳黏膜,铺片及扫描电镜观察耳蜗毛细胞的形态学变化。结果 ABR阈值正常值为(8.2±2.8)dB,经照射后的3组实验动物ABR阈值均较正常值升高并呈随时间推移逐渐升高的趋势。ABR阈值在第3天、第2周和第2个月的时间段,地塞米松组分别是:(24.0±14.1)、(27.1±9.9)和 (38.0±15.1)dB;单纯照射组分别是:(24.5±13.5)、(39.5±15.4)和(57.2±18.4 )dB;盐水对照组分别是:(27.0±14.6)、(42.8±13.5) dB(本组仅观察第3天和第2周)。其中,地塞米松组在术后第2周和第2月ABR阈值较其他两组降低,差异具有统计学意义( P <0.05)。在基底膜铺片和扫描电镜下观察中,健康对照组外毛细胞缺失为(8.0±2.7)个,内毛细胞缺失为(3.7±1.2)个。照射后的3组动物的内、外毛细胞的缺失数量均有明显增加,且外毛细胞多于内毛细胞。各组均表现为随时间推移缺失数逐渐增加的趋势。在术后第2周和第2个月,地塞米松组比单纯照射组的外毛细胞缺失个数减少,分别为(30.7±7.6)与(60.3±14.5)和(67.3±7.0)与(100.0±5.3),两者的差异均有统计学意义( P <0.05)。扫描电镜观察发现,照射后耳蜗毛细胞表现为纤毛倒伏,融合或缺失其中以第3排外毛细胞为重,并随时间推移而加重。地塞米松组的毛细胞损害在第3天和第2周较其他组轻,但在第2个月时没有明显差异。结论 经圆窗膜给地塞米松可以在一定的程度上减轻大剂量放射所造成的豚鼠的内耳损害。 |
| 英文摘要: |
| Objective To investigate the protective effect of dexamethasone applied to round window membrane (RWM) against radiation-induced inner ear damage in guinea pigs, in order to provide the evidence for preventing and treating radiation-induced inner ear damage. Methods 130 guinea pigs were randomly divided into four groups. (1) Dexamethasone group(n=45): The guinea pigs were injected with dexamethasone through an intact RWM on right ear for one time after being treated with 70 Gy60Coγ irradiation. (2) Irradiation group(n=45): The guinea pigs were treated with 70 Gy60Coγ irradiation. (3) Saline group (n=30): Applying of normal saline through an intact RWM on right ear for one time after being treated with 70 Gy60Coγ irradiation. (4) Control group(n=45): Auditory brainstem response (ABR) was tested before the 3rd day, the second week and the second month after irradiation (treatment) in the first three groups. The animals were sacrificed right after the ABR test and the middle ear mucosa was observed simultaneously. The hair cells were observed by surface preparation of the basilar membrane and scanning electron microscope (SEM). Results The normal ABR threshold is (8.2±2.8) dB. The ABR thresholds increased in those of the three groups treated with irradiation and were rising with time. At the 3rd day, the second week and the second month, ABR thresholds of the dexamethasone group were (24.0±14.1), (27.1±9.9) and (38.0±15.1)dB, respectively, while the irradiation group were (24.5±13.5), (39.5±15.4) and (57.2±18.4) dB. The saline group were (27.0±14.6) and (42.8±13.5)dB, respectively. ABR thresholds of the dexamethasone group at the second week and the second month both decreased compared with those of the irradiation group and saline group(P<0.05) . In the control group, the outer hair cell lost by 8.0±2.7 and inner hair cell by 3.7±1.2. The lost quantities of the inner hair cells and outer hair cells were decreased significantly in the three groups with irradiation, and outer hair cells were more than inner hair cells. The loss of hair cells was increased gradually in all groups with irradiation. At the second week and the second month, the loss of outer hair cells in the dexamethasone group were less than those in irradiation group, which were 30.7±7.6 vs. 60.3±14.5 and 67.3±7.0 vs. 100.0±5.3 (P<0.05). The SEM showed the fusion, loss, lodging and other pathological changes in stereociliary bundle and the losses of hair cell, which were more serious. Those of pathological changes in the dexamethasone group were weaker than those in the groups with irradiation at the 3rd day and the second week. Conclusions Application of dexamethasone through intact RWM could reduce the extent of radiation-induced inner damage. |
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