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Influences of Caloric Restriction on Age‐associated Skeletal Muscle Fiber Characteristics and Mitochondrial Changes in Rats and Mice a
Author(s) -
LEE CONNIE M.,
ASPNES LAUREN E.,
CHUNG SUSAN S.,
WEINDRUCH RICHARD,
AIKEN JUDD M.
Publication year - 1998
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1998.tb09901.x
Subject(s) - caloric theory , skeletal muscle , biology , mitochondrion , endocrinology , medicine , physiology , genetics
The effect of caloric restriction (CR) initiated in adult rats (17 months of age) on the abundance of deleted mitochondrial genomes, mitochondrial enzymatic abnormalities, and fiber number was examined in rat skeletal muscle. Vastus lateralis muscle from young (3‐4 months) ad libitum ‐fed, old (30‐32 months) restricted (35% and 50% CR, designated CR 35 and CR 50 , respectively), and old ad libitum ‐fed rats (29 months) was studied. CR preserved fiber number and fiber‐type composition in the CR50 rats. In the old rats from all groups, individual fibers were found with either no detectable cytochrome‐ c oxidase activity (COX − ), hyperactive for succinate dehydrogenase activity (SDH ++ ), or both COX − and SDH ++ . Muscle from the CR 50 rats contained significantly fewer COX − and SDH ++ fibers than did the muscle from the CR35 rats. CR50 rats also had significantly lower numbers of mtDNA deletion products in two (adductor longus and soleus) of the four muscles examined compared to CR35 rats. These data indicate that CR begun in late middle age can retard age‐associated fiber loss and fiber‐type changes as well as lower the number of skeletal muscle fibers exhibiting mitochondrial enzyme abnormalities. CR can also decrease the accumulation of deleted mitochondrial genomes.