Aratmodelofchronictympanicmembraneperforationwasdevelopedtobeusedinthesearchofnewmaterialsforthesealingoftheseperforations.AlongitudinalstudywascarriedoutinratssubjectedtoincisionalmyringotomyfollowedbytheapplicationofmitomycinCaloneorwithdexamethasone.Ratswerecheckedatdays3,7,10,14andweeklythereafteruntilperforationclosure,forupto6months.Theadditionofdexamethasoneisakeycomponentinordertoobtainachronicopening.Myringotomiestreatedwithsalinehadameanhealingtimeof8.5days.At8weeks,between62.5%and77.7%oftympanicmembranestreatedwithmitomycinCanddexamethasoneremainedperforatedandat6monthsthisnumberfellto21.4%.Thistechniqueisabletomaintainmosttympanicmembraneperforationspatentforatleast8weeks.Thisratmodelisadequateforitsuseinpreclinicalortranslationalresearch.
