ObjectiveTo investigate the expressions of NADPH oxidases (NOX2 and NOX3) in an experimental rat model of tympanosclerosis and their possible roles in the oxidative damage of this disease.MethodsTwenty healthy, adult, male, SpragueDawley rats (40 ears) weighing 250-300 g, were randomly divided into two groups. Of them, 5 (10 ears) were chosen to serve as controls, and the other 15 (30 ears) were used in the experimental group. On the first day, rats in the experimental group received myringotomy to the superiorposterior quadrant of the tympanic membrane of both ears making a perforation of 2 mm diameter, while rats in the control group got no operation. All the rats received otoscopy and were sacrificed on the 18th day. Gene expressions of NOXs in middle ear tissue were detected by reverse transcriptionpolymerase chain reaction (RTPCR). Twoway contingency table logistic regression analysis was adopted to analyze the relationship between tympanic membrane perforation and expression of NOX genes as well as that between tympanosclerosis and expression of NOX genes.ResultsAt the 18th day，sclerotic changes (calcification and opacification) of tympanic membrane were observed in all the rats of the experimental group while no evidence of sclerotic changes in those of the control group. RTPCR showed coincident expressions of NOX2 and NOX3 in most specimens of the experimental group with negative expressions in most specimens of the control group. Twoway contingency table logistic regression analysis revealed that tympanic membrane perforation may activate the expression of NOX genes (P<0.01), which may be related to the occurrence of tympanosclerosis (P<0.01).ConclusionIn the process of tympanosclerosis caused by tympanic membrane perforation, NOX may be an important source of reactive oxygen species which may induce oxidative damage of tympanosclerosis.