MITOTIC RESPONSE OF STRATIFIED SQUAMOUS EPITHELIUM AT EDGE OF LARGE PERFORATIONS OF TYMPANIC MEMBRANE IN GUINEA-PIGS

  • 1 January 1977
    • journal article
    • research article
    • Vol. 124  (DEC) , 731-740
Abstract
Large perforations (50%) of the left TM [tympanic membrane] were made under direct vision using a sharp scalpel blade. Subsequently, mitotic counts were conducted on perforations of 1-28 days duration; no chronic lesions were achieved because the prolific response of the TM after trauma almost invariably resulted in rapid healing. Peaks of mitotic activity were discovered at 2, 15-16 and 24 days after wounding, a response similar to that found in tissues previously studied. The maximal proliferative response was not at the immediate wound edge, as is usually maintained, but some 2 mm from the wound edge. This finding was particularly marked when the overall mitotic number in the area of the wound was low; when it was higher, the mitoses were more evenly distributed. The results were examined in the light of the chalone hypothesis of mitotic control with which they were difficult to correlate. The results could be explained by a decrease in the amount of systemically circulating mitotic control factor(s) as a result of the injury. In the liver and lung, a relationship between mitotic response and blood flow is well documented. This could well apply to the tympanic membrane.