Penicillin reduces new bone formation in acute otitis media

Previous studies have shown that acute otitis media alters modeling dynamics in bone tissue structures surrounding the middle ear cavity. Initial resorption is followed by formative activity, which is seen as massive osteoneogenesis. However, neither resorptive nor formative activity occurs in the otic capsule, supporting the theory on existence of a perilymphatic barrier of specialized bone.

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.

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, initiated on day 2 and lasting 5 (2) days. Using a light microscope, bone histomorphology was registered and the thickness measured in four well-defined localities, followed by comparison with a previous study of untreated animals.

Measured bone thickness was unaffected by treatment on day 4, but significantly reduced in two localities on day 8 and in all localities on following days of sacrifice. Bone cytomorphology and histomorphology were otherwise unaffected by penicillin administration.

Penicillin reduces new bone formation in acute otitis media, leaving other features of histomorphology unchanged.