The role of free oxygen radicals in experimental otitis media.

Free oxygen radicals (FORs); have been implicated as important pathologic mediators in many diseases. Under physiological conditions FORs are part of normal regulatory circuits and neutralized by antioxidants, but an increased flux of FORs can cause tissue damage. Infections are one cause of increased FORs production. An important mechanism of tissue damage produced by FORs is the peroxidation of membrane lipids, which can be estimated by malondialdehyte (MDA) levels. The purpose of this study was to determine in 24 albino rabbits whether FORs play a role in the pathogenesis of otitis media experimentally induced by inoculating Streptococcus pneumonia into the right ear, with the left ear serving as a control. We examined the mucosa of each middle ear histopathologically and measured MDA levels in mucosa and serum. Serum MDA levels in infected rabbits were significantly higher than those in preoperative blood specimens (p<0.05). The MDA levels in mucosa were significantly higher in infected ears than in control ears (p<0.01). In the experimentally infected group, a correlation was found between MDA levels in serum and mucosa (p<0.05). In conclusion, serum and mucosa MDA indicating FORs production increased significantly in experimental otitis media. We considered that FORs might play a role in tissue damage caused by otitis media.