Increased Skeletal Muscle Mass And Improved Contractile Properties Of Skeletal Muscles Of Old Myostatin-deficient Mice

Myostatin inhibits myogenesis. Therefore, we sought to determine if mice lacking the myostatin gene [ Mstn(-/-)] would lose less muscle mass than wild-type mice during 7 days of hindlimb suspension (HS). Male Mstn(-/-) and wild-type (C57) mice were subjected to HS or served as ground-based controls ( n = 6/group). Wild-type mice lost 8% of body mass and ∼13% of wet mass from biceps femoris, quadriceps femoris, and soleus, whereas the mass of extensor digitorum longus (EDL) was unchanged after HS. Unexpectedly, Mstn(-/-) mice lost more body (13%, P < 0.05) and quadriceps femoris (17%, P < 0.05) mass than wild-type mice and lost 33% of EDL mass ( P < 0.01) after HS. Protein expression of myostatin in biceps femoris and quadriceps femoris was not altered, whereas expression of MyoD, Myf-5, and myogenin increased in wild-type mice and tended to decrease in muscles of Mstn(-/-) mice. These data suggest that HS induced myogenesis in wild-type mice to counter atrophy, whereas myogenesis was not induced in Mstn(-/-) mice, thereby resulting in a greater loss of muscle mass.

Download Full-text

Skeletal muscle mass and contractile properties in elderly humans: a longitudinal study

The FASEB Journal ◽

10.1096/fasebj.21.6.lb116-d ◽

2007 ◽

Vol 21 (6) ◽

Author(s):

Roger A. Fielding ◽

Kieran F. Reid ◽

Edward M. Phillips ◽

Lisa S. Krivickas ◽

Virginia A. Hughes ◽

...

Keyword(s):

Skeletal Muscle ◽

Longitudinal Study ◽

Muscle Mass ◽

Skeletal Muscle Mass ◽

Contractile Properties ◽

Elderly Humans

Download Full-text

Effects of castration and androgen treatment on androgen-receptor levels in rat skeletal muscles

Journal of Applied Physiology ◽

10.1152/jappl.1999.87.6.2016 ◽

1999 ◽

Vol 87 (6) ◽

pp. 2016-2019 ◽

Cited By ~ 52

Author(s):

Jose Antonio ◽

Jean D. Wilson ◽

Fredrick W. George

Keyword(s):

Skeletal Muscle ◽

Androgen Receptor ◽

Muscle Mass ◽

Skeletal Muscles ◽

Skeletal Muscle Mass ◽

Levator Ani ◽

Male Rats ◽

Levator Ani Muscle ◽

Plantaris Muscle ◽

Androgen Treatment

The effects of castration and dihydrotestosterone (DHT) treatment on levels of skeletal muscle androgen receptor (AR) were examined in three groups of adult male rats: 1) intact normal rats, 2) rats castrated at 16 wk of age, and 3) rats castrated at 16 wk of age and given DHT for 1 wk starting at week 17. All animals were killed at 18 wk of age. Castration caused a decrease ( P< 0.05) in the weights of the levator ani and bulbocavernosus muscles. The administration of DHT to the castrated rats increased ( P < 0.05) the weights of the levator ani and bulbocavernosus muscles. Castration caused a significant downregulation of AR levels in the bulbocavernosus ( P< 0.05) but had no significant effect on AR levels in the levator ani muscle. DHT administration to the castrated group upregulated AR levels in the bulbocavernosus and levator ani muscles. The plantaris muscle did not significantly ( P > 0.05) change for any of the treatments. These findings suggest that the effects of castration and androgen replacement differentially affect skeletal muscle mass and AR levels.

Download Full-text

Resveratrol attenuates high-fat diet-induced obesity and the aging-related sarcopenia mitochondrial dysfunction in skeletal muscle

10.1101/823088 ◽

2019 ◽

Author(s):

Chyi-Huey Bai ◽

Javad Alizargar ◽

Jia-Ping Wu

Keyword(s):

Skeletal Muscle ◽

Exercise Training ◽

Muscle Mass ◽

Mitochondrial Function ◽

High Fat Diet ◽

Skeletal Muscles ◽

Skeletal Muscle Mass ◽

Sarcopenic Obesity ◽

High Fat ◽

Samp8 Mice

AbstractSarcopenic obesity is a progressive loss of skeletal muscle mass and strength with increases in adiposity. The aim of this study was to investigate the effects of resveratrol on obesity or sarcopenia to potential therapy risk for skeletal muscle declines in physical function. C57BL/6J male mice were fed either a high-fat diet for 4 weeks and resveratrol (low-, middle-, and high-dose) for 8 weeks to express the obesity effect. Samp8 mice sarcopenia skeletal muscle functional deterioration expressed an age-associated decline. Resveratrol (150 mg/Kg BW, daily) was administered by oral gavage two times a week one month of the experimental period. Exercise training based on adaptations in the muscle is training twice a week for 4 weeks. The skeletal muscles from mice in each group were analyzed by H&E staining, TUNEL and western blot analysis to determine mitochondrial function expression, apoptosis and relative fibrosis signaling. Results of the present study indicate that resveratrol in obesity skeletal muscle is linked to an increase in the expression of mitochondrial function involved in Bcl-2 and PI3K/AKT. On the other hand, resveratrol attenuates sarcopenia Samp8 mice, the age-related loss of skeletal muscle mass and mitochondrial function involved in Bad, caspase 3 and IL-6/ERK1. However, exercise training not find a significant difference in sarcopenia skeletal muscles SAMP8 mice. Exercise training didn’t induce sarcopenia skeletal muscle hypertrophy in sarcopenic SAMP8 mice. Therefore, we suggest that resveratrol as a therapeutic potential in the combination of sarcopenia and obesity, the state called sarcopenic obesity.

Download Full-text