摘要目的 探讨高速加压暴露(模拟潜水)所致兔中耳气压伤模型的建立条件和鼓膜损伤病理过程.方法 雄性新西兰兔22只,随机选取18只进行高速加压暴露(即暴露组),其余4只为空白对照组.空白对照组仅置于加压舱内相同时间而不予高气压暴露.暴露组以21/3指数速率空气加压至0.8 MPa,停留5 s后匀速减压至常压出舱.于暴露后当天(0 d)、3d、7d采集双侧鼓膜(动物数分别为10,4和4),采用大体解剖,光学显微镜和透射电镜等方法观察鼓膜损伤的病理过程.结果 高速加压暴露所致鼓膜穿孔率为2.8％(1/36).对暴露后0d的中耳损伤进行O'neill病理分级,其中Ⅰ级占80％(16/20),Ⅱ级占20％ (4/20).其中鼓膜早期(0 d)病理改变以组织结构破坏、出血、上皮和成纤维细胞凋亡为主,中期(3 d)以上皮细胞水肿为主,晚期(7 d)基本恢复正常组织形态,仅见不可逆的中间层弹力纤维结构紊乱.结论 经高速加压暴露后兔鼓膜经历为期7 cd的损伤-修复过程,此过程基本可逆,因此可通过该模型反映潜水中耳气压伤的病理特点.

abstractsObjective To investigate the conditions for the establishment of the model of middle ear barotrauma induced by rapid air compression in rabbits and the pathological processes involved.Methods Used in the study were 22 male New Zealand rabbits,of which 18 were exposed to rapid air compression and were assigned as the exposure group,and the remaining 4 rabbits were assigned as the control group.The rabbits in the control group were just placed in the chamber for the same length of time as the exposure group,but without pressure exposure.The rabbits in the exposure group were pressurized with air to a pressure of 0.8 MPa at an exponential rate of 21/3 and stayed at the said pressure for 5 seconds,and were then decompressed to atmosphere pressure at a linear rate of 3 n/s.Bilateral tympanic membrane samples were harvested at 0,3 and 7 d after exposure,and 10,4 and 4 animals were respectively used for the study.The pathological processes of tympanic membrane were investigated by macroanatomy,light microscopy and transmission electron microscopy.Results The rate of tympanic membrane perforation induced by rapid air compression was 2.8％ (1/36).O'neill pathological grade evaluation at day 0 after exposure indicated that Grade Ⅰ and Grade Ⅱ middle ear barotrauma accounted for 80％ (16/20) and 20％ (4/20) respectively.Initial pathological changes in tympanic membrane was mainly featured by tissue damage,hemorrhage and apoptosis of epithelial cells and fibroblasts at day 0,by epithelial edema at day 3,and near recovery of tissue morphology at day 7,except for irreversible disordered arrangement of elastic fibers in middle layer.Conclusion Following exposure of rapid air compression,rabbit tympanic membrane undergoes a damage-repair process of about 7 days and this process appears to be reversible.Consequently,the animal model could partially reflect pathological features of middle ear barotrauma experienced in diving.