氨磷汀对早期中耳放射损伤防护作用的研究

Morphological observation of amifostine's protective effect on radiation induced early middle ear injury

目的探讨氨磷汀对早期中耳放射损伤的防护作用。方法将38只豚鼠分为A、B、C、D、E5组,其中E组为空白对照,A、C组为单纯照射,B、D组为照射加用氨磷汀。照射豚鼠以60钴γ射线照射右耳,3.0Gy/次,总剂量45Gy,每周5次。加用氨磷汀的豚鼠每次照射前30min腹腔内注射氨磷汀100mg/kg。分别于照射45Gy后第2天和第30天处死豚鼠,行光镜及扫描电镜检查,观察各组豚鼠照射侧中耳黏膜病理和超微结构改变。结果经45Gy射线照射后第2天,豚鼠中耳黏膜上皮增厚,炎性细胞浸润,纤毛倒伏、融合,渗出增多;照射后第30天中耳黏膜上皮纤毛脱落、减少,损伤加重;照射前应用氨磷汀的豚鼠中耳黏膜均未见明显损伤;未用药组较用药组中耳黏膜厚度及白细胞浸润数增高(均P<0.01)。结论射线可致中耳黏膜黏液纤毛输送系统功能受损,并随时间推移而加重;氨磷汀可以减轻中耳的早期放射损伤,可望用于临床。

Objective：To assess the radio-protective effect of amifostine on the middle ear in animal models by observing the morphological changes of middle ear mucosa. Method： Adult guinea pigs（ n = 38） were divided into the radiation group, the radiation＋amifostine group and the control group. The first two groups were exposed to total 45 Gy of Gamma radiation which was administered to the right ear of each guinea pig with 3.0 Gy/fraction, 5 times per week, using a cobalt-60 machine. And the radiation＋amifostine group was pretreated with the radioprotector amifostine 100 mg/kg intra-peritoneally 30 min before each fraction of radiation. Sterile saline was administered intra-peritoneally in radiation group before cad irradiation. Two normal guinea pigs given no treatment were chosen as the control. The tympanic bullas were removed and the mucosae was processed for light microscope and scanning electron microscope examination on the 2nd and 30th days post irradiation to observe mucosa thickness, leukocyte and cilia. Result： Light microscope and scanning transmission electron microscope examination showed in radiation groups that the middle ear effusion occurred; the cilia and micro cilia fell off, fused or eollapsed; their directions changed; the mucosa became thicker; and leukocytes were also found infiltrating into the mucosa. On the 30th day, the damage was more serious. As comparison, there was no manifest damage of the middle ear mucosa in radiation＋ amifostine group. The mucosa thickness and the leukocyte quantity of radiation group were obviously higher than that of radiation＋ amifostine group（ P 〈0.01 ）. Conclusion： The middle ear mucosa was found to change over time after irradiation. Amifostine has a protective effect on radiation induced early middle ear injury.