Key result
Functional overload increased plantaris muscle cross-sectional area by 69% and peak isometric tension by 73% in 25-month-old rats (P<0.05), demonstrating conserved plasticity in extreme old age.
Why the study?
Does extreme old age attenuate plantaris muscle hypertrophy in response to mechanical overload in male Fischer 344 rats?
Does extreme old age attenuate plantaris muscle hypertrophy in response to mechanical overload in male Fischer 344 rats?
p-value: p=<0.05
Plantaris muscle mass and plasticity in response to increased mechanical load are well conserved in very aged male Fischer 344 rats.
Conserved plasticity in aged rat muscle; leaves open translation to human sarcopenia or exercise interventions.
PURPOSE: The present study examined the effect of extreme old age on the plasticity of the rat plantaris muscle in response to an increase in mechanical load. METHODS: Male Fischer 344 rats, aged 7 months (adult) and 25 months (old) underwent bilateral surgical ablation of the gastrocnemius muscle to functionally overload (OV) the fast-twitch plantaris muscle for 8 wk RESULTS: At 27 months of age, plantaris wet weight and cross-sectional area (CSA) were unaffected by age, but aging decreased peak isometric tension (Po) 27% (P < 0.05). Plantaris muscle myosin heavy chain composition indicated a loss of faster myosin heavy chains (MHC) isoforms with concomitant increases in slower MHC in old rats (P < 0.05). In adult rats, OV increased muscle CSA and Po 72% and 83%, respectively (P < 0.05). Similarly, OV increased CSA and Po 69% and 73%, respectively, in old rats (P < 0.05). Average fiber CSA increased 57% and 68% in adult-OV and old-OV rats, respectively (P < 0.05). CONCLUSION: Collectively, our data indicate that plantaris muscle mass and plasticity in response to increased mechanical load are well conserved in very aged male Fischer 344 rats.
No takes yet. Share an insight, caveat, or question.
Linderman et al. (2002) studied Muscle hypertrophy and aging. Bilateral surgical ablation of the gastrocnemius muscle (functional overload) vs. Adult rats (7 months) vs Old rats (25 months) was evaluated on Plantaris muscle cross-sectional area (CSA) and peak isometric tension (Po) (p=<0.05). Functional overload increased plantaris muscle cross-sectional area by 69% and peak isometric tension by 73% in 25-month-old rats (P<0.05), demonstrating conserved plasticity in extreme old age.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: