鼓室硬化豚鼠中耳黏膜电镜下超微结构特点

Electron-Microscopic Studies in Guinea Pig with Tympanosclerosis

目的了解豚鼠鼓室硬化中耳黏膜电镜下的超微结构特点,以探讨豚鼠鼓室硬化的发病机理。方法健康杂色豚鼠8只为研究对象,其中,6只(8耳)行鼓室硬化造模,2只(4耳)为正常对照。鼓室硬化的造模方法为显微镜下经豚鼠鼓膜紧张部后下象限向鼓室内注射1×108个/L金黄色葡萄球菌液100μl,观察6个月以上,观察期间不给任何治疗。以显微镜下可见鼓膜穿孔边缘或鼓室腔有钙化斑为造模成功标准。取鼓室硬化造模成功豚鼠不同部位的中耳黏膜及正常豚鼠相应部位的中耳黏膜分别在电镜下观察其超微结构。结果正常豚鼠中耳黏膜胶原纤维少,纤维细胞形态大小正常,粗面内质网、线粒体形态正常,有线粒体嵴,无溶酶体。鼓室硬化中耳黏膜纤维细胞呈不规则变形、伸长、退变,细胞核深染呈卵圆形,核周的胞浆内有肿胀线粒体和变性溶酶体聚集,内质网扩张成囊状,黏膜下层细胞基质中含大量的胶原纤维,在基质胶原纤维束间有大量无定形的富含高密度电子的小体。结论豚鼠鼓室硬化中耳黏膜电镜下见胶原纤维显著增生,细胞基质小囊泡、胞内溶酶体、脂质颗粒内的磷脂结构均有钙化,但主要发生在细胞基质小囊泡。

Objective To study the middle ear mucosa of guinea pigs with tympanosclerosis by electron microscope and try to obtain ：some insights into the feature and pathogenesis of tympanosclerosis. Methods Eight healthy variegated guinea pigs were devided into 2 groups. Six（8 ears） guinea pigs were subjected to inoculation of 1 × 108/L of staphylococcus aureus solution 100 μl into the middle ear cavities under the microscope. All the guinea pigs were observed for more than 6 months with no farther treatment. For electron microscopic studies,the mucosa tissues were taken from the tympanic mucosa in 6 guinea pigs （8 ears）with tympanosclerosis from various sites, while the middle ear mucosa of two healthy guinea pigs （4 ears）were taken as a control. Results Ultrastructural examination of the normal middle ear mucosa revealed a few collagen fibers, normal morphous of fibrocyte, rough endo- plasmic reticulum and mitochondria,and there was no lysosome. However, the tympanosclerosis specimens showed that irregular deformation, elongation,and degeneration of fibrocytes and oval nucleus were darkly stained, lots of mitochondria and lysosomes gathered into the cytoplasm around the nuclear and cystic expansion of the endoplasmic reticulum. In the submucosa extracellular matrix, there were a large number of collagen fibers containing lots of a morphous high--density electron--rich body. Conclusion Electron-microscopic studies of the middle ear mucosa of guinea pigs with tympanosclerosis revealed evident proliferation of collagen fibers, and calcifications were seen in the structures such as extracellular matrix vesicle, lysosomes, myelin structures within lipid granules, which mainly in extracellular matrix vesicles.