Electron-Microscopic Studies in Guinea Pig with Tympanosclerosis / 听力学及言语疾病杂志

ABSTRACT

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 1×10~8/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 Uhrastructural examination of the normal middle ear mucosa revealed a few collagen fibers,normal morphous of fibrocyte,rough endoplasmic 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 amorphous 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.