Fine structure of the rat tympanic membrane after treatment with local anaesthetics.
The tympanic membrane of the rat was studied ultrastructurally after application of a local anaesthetic--lidocaine spray. Already after 10 min, degenerative changes--or even necrosis--were observed on both epithelial surfaces of the eardrum. Later on, a marked hyperplasia of the epidermal layer was most characteristic, as was a proliferation of the fibroblasts of the subepithelial connective tissue. After 3 weeks the eardrum had not regained its normal appearance. No perforations were encountered and only minute substructural changes could be detected within the fibrous layer.
D000336:Aerosols; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014432:Tympanic Membrane / Q000187:drug effects / Q000648:ultrastructure*
D000336:Aerosols; D000779:Anesthetics, Local; D008012:Lidocaine