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Proteolytic gene expression at rest and following acute resistance exercise in young and old women
Author(s) -
Raue Ulrika,
Slivka Dustin,
Jemiolo Bozena,
Hollon Chris,
Trappe Scott
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a803-b
Subject(s) - endocrinology , medicine , apoptosis , messenger rna , vastus lateralis muscle , gene expression , resistance training , chemistry , biology , andrology , skeletal muscle , gene , biochemistry
The purpose of this investigation was to analyze mRNA expression of 7 proteolytic markers before (rest) and 4‐h after a single bout of resistance exercise (RE) in young and old women. The markers of interest were: Atrogin‐1, muscle RING finger 1 (MuRF‐1), Forkhead box 3A (FOXO3A), cysteine‐dependent aspartate protease (Caspase)‐3, B‐cell leukemia/lymphoma (Bcl)‐2, Bcl‐2 associated X protein (Bax) and tumor necrosis factor (TNF)‐α. Eight young women (YW) (23 ± 2 y, 67 ± 5 kg) and 6 old women (OW) (85 ± 1 y, 67 ± 4 kg) performed knee extensions for 3 sets of 10 repetitions at 70% of 1‐repetition maximum. Muscle biopsies were taken from the vastus lateralis before and 4‐h after RE. Using real‐time RT PCR, mRNA from the muscle samples was amplified and normalized to GAPDH. CT scans of the thigh revealed YW had greater (p<0.05) muscle mass (122.0 ± 5.6 cm 2 vs. 89.4 ± 3.7 cm 2 ) compared to OW. In addition, the YW were stronger (p<0.05) (1‐RM: 60.2 ± 5.9 kg vs. 38.8 ± 2.6 kg) than the OW. At rest OW expressed higher (p < 0.05) mRNA levels of MuRF‐1, FOXO3A and Caspase‐3, compared to YW. In response to RE, YW had an increase (p < 0.05) in MuRF‐1 (282 ± 70%) mRNA. With RE, the OW had an increase (p < 0.05) in both Atrogin‐1 (142 ± 35%) and MuRF‐1 (157 ± 33%) mRNA. In summary, OW had higher mRNA resting levels in 3 out of 7 selected proteolytic markers compared to YW. With RE, the increased mRNA induction of the ubiquitin/proteasomal markers was greater for OW compared to YW. These data support that aging alters the regulation of muscle proteolysis at rest and in response to RE, which may contribute to the age‐associated muscle loss. Supported by NIH grant AG18409