TY - JOUR
T1 - Muscle function and protein metabolism after initiation of eccentric contraction-induced injury
AU - Lowe, D. A.
AU - Warren, G. L.
AU - Ingalls, C. P.
AU - Boorstein, D. B.
AU - Armstrong, R. B.
PY - 1995
Y1 - 1995
N2 - This study was designed to determine the relationship between skeletal muscle function and protein metabolism after initiation of eccentric contraction-induced injury. Mouse anterior crural muscles were injured in vivo, and then either immediately or 3, 6, 24, 48, 72, 120, or 336 h after injury muscles were isolated and studied for indexes of muscle function, injury, phagocyte infiltration, and protein metabolism. A group of mice were administered anti-polymorphonuclear cell and anti-macrophage antisera in an attempt to reduce phagocytic infiltration into injured muscle. Force production in extensor digitorum longus muscles was reduced 55% immediately after injury induction and did not recover significantly until 120 h postinjury (28% below baseline). However, rates of protein degradation were not elevated until 48 h postinjury (60% above normal) and were not correlated with the changes in force production (r = -0.37; P = 0.24). Phagocytic infiltration was evident 24-120 h postinjury and was correlated with the elevated protein degradation rates (r = 0.75; P < 0.01). Protein synthesis rates began to increase ~48 h after injury was induced and were elevated by 83% 5 days postinjury. Fourteen days after injury, muscle protein degradation and synthesis rates had returned to normal, as well as specific force production, and phagocytic infiltration was not detected. However, muscle mass, protein content, and absolute force production were lower than normal. Antisera-treated mice were rendered neutropenic, but there was no difference in any variable measured between muscles from these mice and muscles from normal mice.
AB - This study was designed to determine the relationship between skeletal muscle function and protein metabolism after initiation of eccentric contraction-induced injury. Mouse anterior crural muscles were injured in vivo, and then either immediately or 3, 6, 24, 48, 72, 120, or 336 h after injury muscles were isolated and studied for indexes of muscle function, injury, phagocyte infiltration, and protein metabolism. A group of mice were administered anti-polymorphonuclear cell and anti-macrophage antisera in an attempt to reduce phagocytic infiltration into injured muscle. Force production in extensor digitorum longus muscles was reduced 55% immediately after injury induction and did not recover significantly until 120 h postinjury (28% below baseline). However, rates of protein degradation were not elevated until 48 h postinjury (60% above normal) and were not correlated with the changes in force production (r = -0.37; P = 0.24). Phagocytic infiltration was evident 24-120 h postinjury and was correlated with the elevated protein degradation rates (r = 0.75; P < 0.01). Protein synthesis rates began to increase ~48 h after injury was induced and were elevated by 83% 5 days postinjury. Fourteen days after injury, muscle protein degradation and synthesis rates had returned to normal, as well as specific force production, and phagocytic infiltration was not detected. However, muscle mass, protein content, and absolute force production were lower than normal. Antisera-treated mice were rendered neutropenic, but there was no difference in any variable measured between muscles from these mice and muscles from normal mice.
KW - exercise
KW - muscle stretch
KW - protein degradation
KW - protein synthesis
KW - skeletal muscle
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U2 - 10.1152/jappl.1995.79.4.1260
DO - 10.1152/jappl.1995.79.4.1260
M3 - Article
C2 - 8567571
AN - SCOPUS:0028863240
SN - 8750-7587
VL - 79
SP - 1260
EP - 1270
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 4
ER -