Lipoperoxidation As a Measure of Free Radical Injury in Otitis Media

Abstract

Free radical damage, as evidenced by lipoperoxidation, has previously been demonstrated to contribute to the inflammatory changes associated with acute otitis media. The present study was undertaken to evaluate whether lipoperoxidation continues to be present for a period of time after middle ear infection. Eighty-two 300- to 400-g guinea pigs were injected with Streptococcus pneumoniae in the left ear and sterile saline in the right ear as a control. Animals were examined and sacrificed on day 5, 10, 20, or 30; middle ear mucosa was harvested and assayed for lipid hydroperoxide content. A statistically significant increase in lipoperoxidation was seen at each time point studied, compared with controls. Lipoperoxidation was highest at days 5 and 10; a significant decrease was seen at days 20 and 30. Histologic sections of middle ear mucosa of two animals per group were prepared and evaluated for inflammation. These results demonstrate that lipoperoxidation may contribute to middle ear inflammation for a significant period of time after acute infection; the findings are discussed in light of other work on the role of free radicals in otitis media.

Oxidant and antioxidant levels in children with acute otitis media and tonsillitis: A comparative study

“…Furthermore, when compared the AOM and AT groups, there was statistically significant difference between the groups (Table 1). Many investigators, both experimental [16][17][18][19][20] and human [21][22][23][24][25] studies have measured lipid peroxidation levels in AOM and acute or chronic tonsillitis. These studies also demonstrated that increased oxidative stress in the both diseases.…”

Free Radical Production by Antibiotic‐Killed Bacteria in the Guinea Pig Middle Ear

“…Biochemical analysis of the mucosa has demonstrated elevated levels of LPO, which is an indication of FR‐mediated lipid damage after infection. 2,3 …”

“…In this model, FRs are hypothesized to be generated by both S. pneumoniae and neutrophils responding to infection. 2,3 …”

“…In this model, FRs are hypothesized to be generated by both S. pneumoniae and neutrophils responding to infection. 2,3 Since FRs seem to be involved in the pathogenesis of otitis media, it is important to understand the mechanism of damage and to adopt protocols that inhibit such damage. The objective of this study is to elucidate the role of antibiotic-killed S. pneumoniae in the pathogenesis of FRmediated damage to the ME mucosa in AOM.…”

Can Eustachian Tube Ventilatory Function Impairment After Oxygen Diving Be Influenced by Application of Free Radical Scavenger Vitamins C and E?

“… 8 Lipoperoxidation caused by free radicals may contribute to middle ear inflammation after acute infection. 9 …”