MRI Quantitative Analysis of Eccentric Exercise-induced Skeletal Muscle Injury in Rats

Abstract

Background: The aim of this study was to investigate the value of magnetic resonance (MR) quantitative analysis (MR-T2 mapping technique) for the evaluation of eccentric exercise-induced skeletal muscle injury. Materials and Methods: We established an animal model of eccentric exercise-induced damage of Sprague Dawley rat skeletal muscle and evaluated the animals by MR imaging, determined the serum levels of fast skeletal troponin (fsTnI), and examined muscle histopathology, at 0, 1, 2, 4, and 7 days after eccentric exercise. The associations between MR imaging findings, and histopathological and laboratory results were evaluated. Results: T2-weighted images (WIs) of quadriceps femoris muscles showed obvious high signal intensities after exercise, and the T2 values and serum fsTnI levels continued to increase, peaking at day 2 after exercise, p< 0.05. The histopathological findings in muscle specimens, which included swollen and ruptured cells, enlarged extracellular spaces, inflammation, and regeneration of muscle fibers, showed similar trends. After day 2, muscle specimens began to show evidence of self-repair, the T2WI signals decreased in intensity, and the T2 values and serum fsTnI levels decreased; however, at day 7 post injury, the values remained slightly higher than those in the control animals, p< 0.05. The T2 value was significantly correlated with the serum fsTnI level (r = 0.896, p< 0.01). Conclusion: T2 mapping technology accurately reflects the histopathological and fsTnI abnormalities and the degree of skeletal muscle damage associated with eccentric exercise followed by recovery. Because T2 mapping technology is noninvasive and can be quantitatively analyzed, it might become the preferred method for performing the diagnosis of eccentric exercise-induced skeletal muscle injury.

Aerobic Metabolic Adaptations in Endurance Eccentric Exercise and Training: From Whole Body to Mitochondria

“…In addition to histological alterations, symptoms of muscle soreness associated with increased intramuscular compartment pressure appear within 24 h of exercise and extend over several days. Exercise-induced damage confirmation showing maximal swelling occurring between 4 and 7 days post-exercise has been provided in both humans and animal muscles using ultrasound elastography, magnetic resonance imaging, and quantitative analysis approaches (McHugh, 2003;Lacourpaille et al, 2014;Fu et al, 2020). An elevation in blood creatine kinase activity 24-48 h post-exercise reflecting myofiber membrane disruption is also a consistent finding after eccentric exercise, the magnitude of increase being related to the exercise intensity (Balnave and Thompson, 1993;Malm et al, 2004;Klossner et al, 2007;Frimpong et al, 2019).…”

“…The extent to which the "repeated bout effect" contributes to the adaptation occurring during the familiarization period of an eccentric training program is difficult to establish clearly. Results from a study in rats using a combined magnetic resonance imaging and skeletal muscle histopathological analysis to explore the kinetics of eccentric exercise-induced injury showed maximal disruption to be seen at day 2 post-exercise with gradual muscle repair continuing until at least day 7 (Fu et al, 2020). In contrast to most investigations of repeated bouts effects in which there is a long period separating an initial and a second exercise, familiarization is characterized by successive exercise bouts separated by short rest periods.…”

Effect of Aquatic Exercise After Eccentric Contraction-Induced Muscle Injury

“…Daniel Boeira 1,2 (Physical Education Professional) Ramiro Doyernart 1,2 (Physical Education Professional) Fernanda Sombrio 1,2 (Physical Education Professional) Julia Santos Medeiros 1,2 (Physical Education Professional) Iuri Pinheiro Milhomens 1,2 (Physical Education Professional) Gabrielli Brina de Souza 1,2 (Physical Education Professional) Luciano Acordi da Silva 1,2 (Physical Education Professional)…”

“…Initially, mechanical factors (contraction and stretching) produce sarcomere rupture, impairment of actin/myosin coupling and calcium signaling, and degradation of the sensory receptors that are metabolically involved. 1,2 Previous studies carried out in our laboratory 2,3 suggest that ECs cause microlesions, thereby changing parameters of strength, performance, inflammation, and oxidative stress for an extended period. This represents cause for concern in the world of sports, since the recovery time between one sport activity and another can be extremely short.…”

A Longitudinal Study of T2 Mapping Combined With Diffusion Tensor Imaging to Quantitatively Evaluate Tissue Repair of Rat Skeletal Muscle After Frostbite

“…Acute activity or inflammation will cause the T2 value to rise. In clinical trials, T2 mapping can quantitatively evaluate skeletal muscle injury and myocardial infarction (Zhang et al, 2011;Radunski et al, 2017;Fu et al, 2019). Diffusion tensor imaging (DTI) parameters include three eigenvalues (λ1, λ2, and λ3), fractional anisotropy (FA), and mean diffusivity (MD).…”