CRON Prevents Decline in Auditory Function

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Hi folks:

Neurobiol Aging. 2006 Aug 3; [Epub ahead of print]

" Caloric restriction suppresses apoptotic cell death in the mammalian

cochlea and leads to prevention of presbycusis. "

Someya S, Yamasoba T, Weindruch R, Prolla TA, Tanokura M.

" Presbycusis is characterized by an age-related progressive decline

of auditory function, and arises mainly from the degeneration of hair

cells or spiral ganglion (SG) cells in the cochlea. Here we show that

caloric restriction suppresses apoptotic cell death in the mouse

cochlea and prevents late onset of presbycusis. Calorie restricted

(CR) mice, which maintained body weight at the same level as that of

young control (YC) mice, retained normal hearing and showed no

cochlear degeneration. CR mice also showed a significant reduction in

the number of TUNEL-positive cells and cleaved caspase-3-positive

cells relative to middle-age control (MC) mice. Microarray analysis

revealed that CR down-regulated the expression of 24 apoptotic genes,

including Bak and Bim. Taken together, our findings suggest that loss

of critical cells through apoptosis is an important mechanism of

presbycusis in mammals, and that CR can retard this process by

suppressing apoptosis in the inner ear tissue.

PMID: 16890326

Rodney.