Myringosclerosis Caused by Increased Oxygen Concentration in Traumatized Tympanic Membranes Experimental Study

Abstract

The purpose of this study was to elucidate possible relationships between the oxygen concentration of the middle ear cavity and the development of myringosclerosis. Three groups of rats with myringotomized tympanic membranes were exposed to different oxygen concentrations of 10%, 15%, and 40%, respectively, for 1 week. A fourth group was kept in ambient air. Two other groups of rats with myringotomized and intubated tympanic membranes were exposed to oxygen concentrations of 10% and 40%, respectively, for the same period of time. Otomicroscopically, all hyperoxic animals had more numerous myringosclerotic lesions compared with the ambient air group, and also displayed a pronounced hyperplasia of the keratinizing epithelium around the perforation border. By contrast, the hypoxic animals showed less pronounced myringosclerotic lesions or even completely lacked them. It is inferred that an increased oxygen concentration in the middle ear cavity will increase the likelihood of myringosclerotic deposits. The mechanism involved could be related to the formation of oxygen radicals.

Does Resveratrol Have a Protective Effect on Tympanosclerosis Formation in Experimentally Induced Otitis Media?

“…TS affects the connective tissue layer and is characterised by an increase in collagenous fibres and hyaline degeneration. Many factors involved in wound healing may play a role in this pathological process [1][2][3][4] .…”

“…One of them suggests that oxygen-derived free radicals may be an aetiological factor in the development of TS [3,5] . However, Atmaca et al [28] demonstrated that exogenous nitric oxide application did not alter the occurrence of TS.…”

“…Tympanosclerosis affects the tympanic membrane (TM) and middle ear, and is characterised by hyaline degeneration in the lamina propria and formation of calcium plaques. Although the aetiology of TS has not been demonstrated exactly, it has been suggested that multiple factors, such as nitric oxide, oxygen free radicals, cytokines, inflammatory mediators, and growth factors contribute to the pathogenesis of TS [1][2][3][4][5] .…”

“…After several studies pointed to a relationship between free oxygen radicals and the development of TS [3,6] , the preventive effects of different antioxidants were investigated. L-carnitine, N-acetylcysteine, caffeic acid, ginkgo biloba, and alpha-tocopherol are the most studied antioxidants in experimentally induced myringosclerosis after myringotomy [7][8][9][10][11] .…”

The Effect of Alpha-Lipoic Acid on Myringosclerosis in a Rat Model

“…MS or TS frequently follows a myringotomy, ventilation tube insertion, recurrent otitis media, physical trauma, and middle ear infections. In addition, a genetic predisposition, immunological sensitivity, and local metabolic changes are factors that predispose a person to the development of TS [3][4][5] . Although the etiopathogenesis of MS is not fully understood, recent studies have reported that reactive oxygen samples (ROS), mechanical injury, and inflammatory diseases are the main factors in the development of MS, and antioxidant agents, free radical connective substances, and anti-inflammatory agents are effective in preventing MS [4,6] .…”