Spontaneous healing of various tympanic membrane perforations in the rat.
OBJECTIVE
To investigate the spontaneous healing process of various types of perforation and the location of the epithelial generation center in the tympanic membrane of rats.


METHODS
Various types of perforation were made in the ears of 50 rats and the healing process was observed using light and electron microscopy.


RESULTS
Epithelia hyperplasia could not be seen at the edge of the perforations, but occurred in the annulus and handle of malleus regions during the early stage of healing. There was no correlation between the healing time and the size of the perforations. When one ear was perforated, no changes were observed in the intact ear on the other side. The epithelium did not migrate into the tympanic cavity in the posterior marginal perforations. All the perforations healed, although the manubria of the malleus were damaged.


CONCLUSIONS
The perforations healed by means of epithelial migration. The epithelial generation center was located near the annulus and the handle of the malleus, and therefore protection of these two regions is very important in middle ear surgery.
Wang
Wu-Qing
WQ
Department of Otolaryngology, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, People's Republic of China. wwuqing@eastday.com
Wang
Zheng-Min
ZM
Chi
Fang-Lu
FL
D000818:Animals; D004848:Epithelium / Q000473:pathology / Q000503:physiopathology; D046529:Microscopy, Electron, Transmission; D051381:Rats; D017207:Rats, Sprague-Dawley; D018058:Tympanic Membrane Perforation / Q000473:pathology / Q000503:physiopathology*; D014945:Wound Healing