Homografts of the tympanic membrane with malleus; histological study in cat.
The present experiments on cats were performed to explore the process of survival and take of transplanted homografts of tympanic membrane with malleus, the homografts being respectively preserved in 4% and 0.5% formalin (pH 7.0) solutions, and to explore the reaction of middle ear mucosa of the recipient. The present study also included gross and histopathological examinations of the eardrum and observation of fibers of the lamina propria of the transplanted tympanic membrane by means of polarizing microscopy and of vascularization by intravascular India ink injection. The experiments conducted using a total of 96 cats yielded results leading to the following conclusions. 1) After six months the transplanted tympanic membrane showed nearly normal histologic features, with a fibrous layer between the lining epithelial and thin mucosal layers. The middle ear mucosa also became thinner and was covered with ciliated epithelium at this stage. 2) As regards vascular distribution, most vessels entered from the peripheral regions to become distributed all over the eardrum with mutual anastomoses. 3) Fibrous tissues of the lamina propria of the pars tensa of the transplanted eardrum remained intact over the six month period. 4) The transplanted malleus was neither destroyed not absorbed, and proved to survive well with active vascularization. 5) The microscopic changes observed in the middle ear mucous membrane of the recipient showed non-specific reactions to Gelfoam. The grafts were not subjected to immunological rejection. Homograft thus offer the best grafting material, but seemed to show poor resistance to infection.
D000818:Animals; D002415:Cats; D003238:Connective Tissue / Q000473:pathology; D004429:Ear Ossicles / Q000637:transplantation*; D006085:Graft Survival; D006965:Hyperplasia; D008307:Malleus / Q000098:blood supply / Q000473:pathology / Q000637:transplantation*; D008866:Microsurgery; D009092:Mucous Membrane / Q000473:pathology; D014184:Transplantation, Homologous; D014432:Tympanic Membrane / Q000098:blood supply / Q000473:pathology / Q000637:transplantation*