Hair cell loss in the aged guinea pig cochlea

The various effects of ageing on the auditory system, collectively termed p resbycusis. are being studied across a wide range of animal species. includ ing humans. One contributing factor to presbycusis is thought to be losses of the sensory hair cells in the cochlea. In this study, hair cell counts w ere obtained From cochleas of pigmented guinea pigs (Cavia porcellus) at ag es ranging from II days to 4 years 7 months, using scanning electron micros copy to visualize the organ of Corti. Representative samples of the basal. middle and apical turn of the cochlea Here photographed for analysis. Hair fell loss was observed, even in young animals. However, the loss was greate r in the aged animals, but was not distributed evenly throughout the length of the cochlea. No significant loss of hair cells was seen in the basal (h igh frequency) or middle turn of the cochlea of the aged animals. In the ap ical (lon frequency) turn, there Has a significant loss of hair cells in al l rows of outer hair cells (up to around 20%), and was most severe in the t hird row. There was no loss of apical inner hair cells in the aged animals.