Dynamics of otosclerosis-like lesions in LP/J mice

The LP/J inbred mouse is the first known animal to spontaneously develop otosclerosis-like bone lesions in the middle and inner ear. These abnormal bone foci resemble human otosclerotic lesions, are inherited, and produce a progressive hearing loss. On the basis of histological evaluation alone, it was unclear whether these otosclerosis-like lesions in LP/J mice develop suddenly or gradually as in human otosclerosis. To study the dynamics of lesion formation, four different colored fluorochrome bone labels were given in sequence to postpubertal LP/J mice and CBA/J mice as normal controls. All of the otosclerosis-like lesions incorporated at least one fluorochrome, and half were labeled with two or more markers indicating continuous lesion growth over many weeks. It appears that otosclerosis-like lesions in LP/J mice develop during early adulthood and progress gradually as in human otosclerosis.