Oral administration of amino acidic supplements improves protein and energy profiles in skeletal muscle of aged rats: elongation of functional performance and acceleration of mitochondrial recovery in adenosine triphosphate after exhaustive exertion.
Sarcopenia is an inevitable age-related degenerative process chiefly characterized by decreased synthesis of muscle proteins and impaired mitochondrial function, leading to progressive loss of muscle mass. Here, we sought to probe whether long-term administration of oral amino acids (AAs) can increase protein and adenosine triphosphate (ATP) content in the gastrocnemius muscle of aged rats, enhancing functional performance. To this end, 6- and 24-month-old male Fisher 344 rats were divided into 3 groups: group A (6-month-old rats) and group B (24-month-old rats) were used as adult and senescent control group, respectively, while group C (24-month-old rats) was used as senescent treated group and underwent 1-month oral treatment with a mixture of mainly essential AAs. Untreated senescent animals exhibited a 30% reduction in total and fractional protein content, as well as a 50% reduction in ATP content and production, compared with adult control rats (p <0.001). Long-term supplementation with mixed AAs significantly improved protein and high-energy phosphate content, as well as the rate of mitochondrial ATP production, conforming their values to those of adult control animals (p <0.001). The improved availability of protein and high-energy substrates in the gastrocnemius muscle of treated aged rats paralleled a significant enhancement in functional performance assessed by swim test, with dramatic elongation of maximal exertion times compared with untreated senescent rats (p <0.001). In line with these findings, we observed that, after 6 hours of rest following exhaustive swimming, the recovery in mitochondrial ATP content was approximately 70% in adult control rats, approximately 60% in senescent control rats, and normalized in treated rats as compared with animals of the same age unexposed to maximal exertion (p <0.001). In conclusion, nutritional supplementation with oral AAs improved protein and energy profiles in the gastrocnemius of treated rats, enhancing functional performance and accelerating high-energy phosphate recovery after exhaustive exertion.
Chen Scarabelli
Carol
C
Center for Heart and Vessel Preclinical Studies, St. John Hospital and Medical Center, Wayne State University School of Medicine, Detroit, Michigan 48236, USA.
McCauley
Roy B
RB
Yuan
Zhaokan
Z
Di Rezze
Justin
J
Patel
David
D
Putt
Jeff
J
Raddino
Riccardo
R
Allebban
Zuhair
Z
Abboud
John
J
Scarabelli
Gabriele M
GM
Chilukuri
Karuna
K
Gardin
Julius
J
Saravolatz
Louis
L
Faggian
Giuseppe
G
Mazzucco
Alessandro
A
Scarabelli
Tiziano M
TM
D000255:Adenosine Triphosphate / Q000378:metabolism; D000284:Administration, Oral; D000375:Aging / Q000473:pathology / Q000502:physiology; D000818:Animals; D019587:Dietary Supplements; D004734:Energy Metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344
D009124:Muscle Proteins; D000255:Adenosine Triphosphate