Concentration-Dependent Effect of Corticosteroid on Mucin in Lipopolysaccharide-Induced Middle Ear Effusi

Research Posters

Adhesions were present in 15% of NF’s and 8% of the FF’s. A TM cholesteatoma was observed in one NF. Inflammation, fibrosis, and cellular ingrowth showed no significant histologic differences between the two groups, though there was a trend toward less inflammation in FF’s. Conclusion: Use of formalin-fixed Alloderm is as safe and efficacious as non-fixed Alloderm in the repair of TM perforations in a chinchilla model. Clinical application is underway to use Alloderm in the technique of fasciaform tympanoplasty. Significance: The success of use of formalin-fixed Alloderm in the chinchilla model allows for the study of the use of this material for total or near-total perforations in humans. Support: none

R504 Up-regulation of RANTES mRNA in Otitis Media Jeong Lim Kim (presenter); Chan Park; Gijung Im, MD; HakHyun Jung, MD, PhD Seoul South Korea; Seoul South Korea; Seoul South Korea; Seoul South Korea

Problem: The aim of the present study was to quantify the expression levels of RANTES mRNA using by competitive PCR in experimentally lipopolysaccharides(LPS)-induced otitis media with effusion (OME) of the rats and also to investigate the expression of RANTES mRNA in middle ear fluid of human otitis media with effusion (OME). Methods: Experimental OME of the rat was induced after middle ear instillation of E. coli lipopolysaccharides. RTPCRs and competitive PCR of middle ear mucosa, taken at 0 h, 1 h, 3 h, 6 h, 12 h, 1day, 3 days, 7 days, and 14 days, were done for RANTES mRNA and ?-microglobulin. We also performed RT-PCR of cDNA from human middle ear fluids of 4 serous and 4 mucoid OME patients for the identification of chemokine mRNA expression, such as IL-8, RANTES, and eotaxin. Results: The relative ratio of ?-microglobulin to RANTES was 0.02 ?0.03% at normal moddle ear mucosa and PBStreated ear, but its ratio increased between 1 h to day 3 after endotoxin instillation. Its expression peaked at day 1 (1.08%) which was approximately 18 folds higher then 0 h and then decreased to 0.04% at day 7 and returned to normal range at day 14. IL-8 mRNA was strongly expressed in all samples and RANTES was strongly expressed in 3 and weakly in 4, but eotaxin was not expressed. Conclusion: These results suggest that RANTES may be primarily responsible for chemotatic attraction for memory T cells and macrophage in OME. Significance: In the present study, RANTES seems to play a significant role in the pathogenesis of OME.”

R505 Concentration-Dependent Effect of Corticosteroid on Mucin in Lipopolysaccharide-Induced Middle Ear Effusi Dennis Fan Chang, MD (presenter); Choong Won Lee, MD; Ryan Gaines; Aron Depew, MD; Jeffrey Smit, MD; Andrew S Florea, MD; Ernest John, PhD; Timothy T K Jung, MD PhD Redlands CA; Riverside CA; Loma Linda CA; Loma Linda CA; Loma Linda CA; Loma Linda CA; Loma Linda CA; Loma Linda CA

Problem: Otitis media (OM) is one of the most common diseases in the pediatric population. Our previous studies showed treatment with systemic antibiotics and corticosteroids were more efficacious than antibiotics alone. Compared to serous otitis media (SOM) and purulent otitis media (POM), mucous otitis media (MOM) tend to be most damaging to hearing, causing the most retraction to tympanic membrane and bone destruction, and does not respond to medical therapy. Because mucin production is the key pathogenic event in MOM progression, the purpose of this study to determine the concentration dependent effect of corticosteroid on mucin production in LPS induced middle ear effusion. Long-term goal of this study is to find better method of treatment of OM especially using topical treatment avoiding systemic side effects. Methods: Five experimental groups were studied (saline, 1% dexamethasone, 0.1% dexamethasone, 1% rimexolone, and 0.1% rimexolone). Otitis media with effusion was induced in all groups of chinchillas by injecting lipopolysaccharide (LPS). All test substances (saline, dexamethasone and rimexolone, 200␮L)) were injected at -2, 48 and 60 hours; LPS was injected at 0 hrs. Animals were monitored with daily otomicroscopy. At the end of 4 days, samples of MEE were collected for the mucin analysis. Results: In saline group (LPS alone) the average amount of mucin (1125 ⫹/- 219 `ı g) was significantly higher (p⫽ 0.05) compared with 1% dexamethasone group (217 ⫹/- 75 `ı g). Average amounts of mucin in 0.1 % dexamethasone (708 ⫹/- 92 `ı g), 1% rimexolone (808 ⫹/- 82 `ı g), and 0.1 % rimexolone group (808 ⫹/- 309 `ı g) were also less compared to saline positive control group. Conclusion: These findings suggest that corticosteroids reduce the production of mucin in LPS induced otitis media. Significance: Corticosteroids can be used for the treatment of mucoid otitis media R506 The Effect of Steroid on Middle Ear Mucosal MUC5AC Expression Shi-Nae Park, MD (presenter); Sangwon Yeo; Choong-Ill Bang, MD; Kyoung-Ho Park, MD Seoul South Korea; Seoul South Korea; Pucheon City South Korea; Seoul South Korea

Problem: Mucus hypersecretion from the midde ear mucosa is a characteristic of otitis media with effusion (OME)

POSTERS

P126

Otolaryngology– Head and Neck Surgery August 2005