Kazikdas K Cagdas, Uguz M Zafer, Erbil Guven, Tugyan Kazim, Yilmaz Osman, Guneli Ensari, Altun Zekiye
Department of Otorhinolaryngology, Ataturk Training and Research Hospital, Izmir, Turkey.
Otol Neurotol. 2006 Sep;27(6):882-6. doi: 10.1097/01.mao.0000224089.00721.8d.
The objective of this study was to investigate the possible effect of alpha-tocopherol on the prevention of experimentally induced myringosclerosis.
Myringosclerosis is a common sequela of ventilation tube treatment of otitis media with effusion. The relationship between oxygen-derived free radicals and occurrence of myringosclerosis has been proven in experimental models, and it was also shown that the formation of myringosclerosis after experimental myringotomy could be reduced by application of various free radical scavengers.
Eighteen Wistar albino rats were myringotomized on the left side and randomly separated into two groups: group A consisted of rats which received intramuscular alpha-tocopherol injections 100 mg/kg daily and group B which were injected with physiological serum only. The occurrence of myringosclerotic plaques in the tympanic membranes of the two groups was compared by otomicroscopy, histopathology, and tympanometry, which is a novel method of quantification. Blood samples were collected for biochemical evaluation, and the tympanic membranes were harvested on the 15th day of the experiment.
In otomicroscopic evaluation, tympanic membranes in group B revealed varying degrees of myringosclerotic plaques; on the other hand, tympanic membranes in group A showed faint or no existence of myringosclerosis. The mean malondialdehyde levels were 1.33 +/- 0.11 micromol/L in group A and 7.49 +/- 1.37 micromol/L in group B (Z = -1.906, p = 0.057). In all ears from group B, the magnitude of the maximum admittance measured by tympanometry reduced to approximately 40% of the values obtained from group A (Z = -2,160, p = 0.031). The mean magnitude of the maximum admittance from group A was very close to the standardization values of Wistar albino rats, which predicts a functional outcome.
The formation of myringosclerosis after experimental myringotomy can be diminished by intramuscular alpha-tocopherol injections.
本研究的目的是调查α-生育酚对预防实验性诱导的鼓膜硬化的可能作用。
鼓膜硬化是分泌性中耳炎通气管治疗的常见后遗症。在实验模型中已证实氧衍生自由基与鼓膜硬化发生之间的关系，并且还表明应用各种自由基清除剂可减少实验性鼓膜切开术后鼓膜硬化的形成。
18只Wistar白化大鼠左侧鼓膜切开，随机分为两组：A组大鼠每天接受100mg/kg肌肉注射α-生育酚，B组仅注射生理血清。通过耳显微镜检查、组织病理学和鼓室导抗测量（一种新的量化方法）比较两组鼓膜中鼓膜硬化斑块的发生情况。采集血样进行生化评估，并在实验第15天采集鼓膜。
在耳显微镜评估中，B组鼓膜显示出不同程度的鼓膜硬化斑块；另一方面，A组鼓膜显示出轻微或不存在鼓膜硬化。A组丙二醛平均水平为1.33±0.11μmol/L，B组为7.49±1.37μmol/L（Z=-1.906，p=0.057）。在B组所有耳朵中，通过鼓室导抗测量测得的最大导纳幅度降至A组获得值的约40%（Z=-2.160，p=0.031）。A组最大导纳的平均幅度非常接近Wistar白化大鼠的标准化值，这预示着功能结果。
肌肉注射α-生育酚可减少实验性鼓膜切开术后鼓膜硬化的形成。
