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Age-related changes in cochlear vascular conductance in mice
J N Brown1, J M Miller, A L Nuttall
1Kresge Hearing Research Institute, University of Michigan, Ann Arbor 48109-0506, USA.
Hearing Research
|June 1, 1995
Summary
Age-related hearing loss involves vascular changes. This study found reduced cochlear blood flow reactivity in presbycusic mice, suggesting altered vascular responsiveness in the aging ear.
Area of Science:
- Otolaryngology
- Vascular Biology
- Gerontology
Background:
- Vascular changes are implicated in age-related hearing loss.
- Mechanisms of microvascular reactivity in the aging ear are not fully understood.
Purpose of the Study:
- To investigate age-related changes in cochlear blood flow (CBF) and vascular reactivity.
- To compare vascular responses between presbycusic mice and age-matched controls.
Main Methods:
- Laser Doppler flowmetry was used to monitor CBF.
- Vascular conductance (VC) response to sodium nitroprusside was assessed.
- Cochlear vascular reactivity was measured in presbycusic (C57BL/6) and control (CBA/J) mice.
Main Results:
- Presbycusic mice showed a blunted VC response (28% increase) compared to young controls (over 40% increase).
- Aged control mice also exhibited a less pronounced VC response.
- VC response recovery was prolonged in presbycusic mice (sustained over 60 min) versus controls (≤50 min).
Conclusions:
- Presbycusic mice exhibit altered cochlear vascular reactivity.
- These findings suggest age-dependent, pathological changes in the aging ear's vascular responsiveness.