The molecular and structural basis of hearing impairment in mice with the cpk mutant gene

We studied hearing impairment and cochlear ultrastructure in C57BL/6J mice containing the cpk mutant gene. Heterozygous cpk/+ mutant mice, 6-8 months old, showed a marked hearing loss as demonstrated by auditory evoked potentials with some showing hearing loss at 90 db sound pressure. Ultrastructural studies of first cochlear turn disclosed the absence of organs of Corti, no tissues on the basilar membrane, scanty spiral ganglia, normal tectorial membrane, and vacuolation of the stria vascularis. Reissner's membrane is normal at the endolymphatic side, but transparent at the perilymphatic side. In the second turn the organ of Corti are normal but Nuel's space is full of debris. The cpk mutant mice have hearing impairment perhaps due to deficiencies of genes expressing vital basement membrane components.