AGE-RELATED-CHANGES IN COCHLEAR BLOOD-FLOW RESPONSE TO OCCLUSION OF ANTERIOR INFERIOR CEREBELLAR ARTERY IN MICE

Previous studies suggest that autoregulation of cochlear blood flow (C BF) may be impaired by aging. In this study, we quantified the capacit y of CBF autoregulation in young adult (6-month-old) and aged (21-mont h-old) CBA mice, to examine the effect of aging on CBF autoregulation. The technique of anterior inferior cerebellar artery (AICA) occlusion was employed to manipulate cochlear perfusion pressure. The CBF was m easured by laser Doppler flowmetry during intermittent occlusion of th e AICA with a microvascular clamp, which causes an initial decrease in CBE The autoregulation of CBF was evaluated by quantifying the CBF in crease (compensatory dilatory response in the cochlear vessels) during AICA occlusion. Our results demonstrated that autoregulation of CBF w as significantly reduced and that collateral vascular function supplyi ng CBF was significantly lower in the aged group. These findings sugge st that the aged ear has less capacity to maintain stable blood flow a nd thus may be more vulnerable to stress factors that affect cochlear function.