Wright C G, Bird L L, Meyerhoff W L
Department of Otorhinolaryngology, University of Texas Southwestern Medical Center, Dallas.
Acta Otolaryngol. 1991;111(1):101-11. doi: 10.3109/00016489109137360.
This study assessed changes in tympanic membrane microstructure associated with cholesteatoma development following middle ear application of 50% propylene glycol in chinchillas. Although the epidermal layer of the tympanic membrane (TM) was destroyed immediately after propylene glycol application, the epidermal basal lamina remained intact and appeared to serve as a substrate for regrowth of epidermis over the TM. During the initial phase of epidermal repair (4 to 7 days after propylene glycol administration), pseudopodial processes from the epidermal cells occasionally penetrated the basal lamina; however, no migration of epidermis into the lamina propria occurred at that time. The basal lamina remained largely intact until about 2 weeks, when it became fragmented in some areas, so that sizable gaps appeared. Hyperplastic epidermal cells then migrated through the gaps into the rapidly proliferating connective tissue of the lamina propria. At 2 to 4 weeks, degenerative changes were observed in portions of the fibrous layer, which underwent phagocytosis by foreign body giant cells. This process created defects in the fibrous layer which permitted invasion of epidermis to the medial portion of the lamina propria. The epidermis subsequently reached the medial side of the TM in areas where there was incomplete repair of the mucosal layer.
本研究评估了在豚鼠中耳应用50%丙二醇后，与胆脂瘤形成相关的鼓膜微观结构变化。尽管在应用丙二醇后鼓膜（TM）的表皮层立即被破坏，但表皮基底层保持完整，似乎为TM上表皮的再生提供了基质。在表皮修复的初始阶段（丙二醇给药后4至7天），表皮细胞的伪足样突起偶尔会穿透基底层；然而，此时表皮并未迁移至固有层。基底层在大约2周前基本保持完整，之后在某些区域开始破碎，出现相当大的间隙。然后增生的表皮细胞通过这些间隙迁移到固有层快速增殖的结缔组织中。在2至4周时，在纤维层的部分区域观察到退行性变化，这些区域被异物巨细胞吞噬。这个过程在纤维层中形成了缺陷，使得表皮能够侵入固有层的内侧部分。随后，在黏膜层未完全修复的区域，表皮到达了TM的内侧。
