Penicillin reduces new bone formation in acute otitis media

Objective: Previous studies have shown that acute otitis media alters model ing dynamics in bone tissue structures surrounding the middle ear cavity. I nitial resorption is followed by formative activity, which is seen as massi ve osteoneogenesis, However, neither resorptive nor formative activity occu rs in the otic capsule, supporting the theory on existence of a perilymphat ic barrier of specialized bone. Study Design: To investigate the effect of penicillin administration on the pathological bone modeling in acute otitis media, we employed a rat model of acute pneumococcal otitis media. Methods : Five rats were sacrificed on postinoculation days 4, 8, 16, 90, and 180, preceded by oral administration of penicillin V 100 mg/kg per day, initiate d on day 2 and lasting 5 (2) days. Using a Light microscope, bone histomorp hology was registered and the thickness measured in four well-defined Local ities, followed by comparison with a previous study of untreated animals. R esults: Measured bone thickness was unaffected by treatment on day 4, but s ignificantly reduced in two localities on day 8 and in all localities on fo llowing days of sacrifice. Bone cytomorphology and histomorphology were oth erwise unaffected by penicillin administration. Conclusion: Penicillin redu ces new bone formation in acute otitis media, leaving other features of his tomorphology unchanged.