Journal Article

Cell‐free DNA kinetics in response to muscle‐damaging exercise: A drop jump study

Brazaitis, Marius, Juškevičiūtė, Ema, Neuberger, Elmo, Eimantas, Nerijus, Heinkel, Kirsten, Simon, Perikles

2024

Overview

A significant increase in circulating cell‐free DNA (cfDNA) occurs with physical exercise, which depends on the type of exertion and the duration. The aims of this study were as follows: (1) to investigate the time course of cfDNA and conventional markers of muscle damage from immediately after to 96 h after muscle‐damaging exercise; and (2) to investigate the relationship between cfDNA and indicators of primary (low‐frequency fatigue and maximal voluntary isometric contraction) and secondary (creatine kinase and delayed‐onset muscle soreness) muscle damage in young healthy males. Fourteen participants (age, 22 ± 2 years; weight, 84.4 ± 11.2 kg; height, 184.0 ± 7.4 cm) performed 50 intermittent drop jumps at 20 s intervals. We measured cfDNA and creatine kinase concentrations, maximal voluntary isometric contraction torque, low‐frequency fatigue and delayed‐onset muscle soreness before and at several time points up to 96 h after exercise. Plasma cfDNA levels increased from immediately postexercise until 72 h postexercise (P < 0.01). Elevation of postexercise cfDNA was correlated with both more pronounced low‐frequency fatigue (r = −0.52, P = 3.4 × 10−11) and delayed‐onset muscle soreness (r = 0.32, P = 0.00019). Levels of cfDNA change in response to severe primary and secondary muscle damage after exercise. Levels of cfDNA exhibit a stronger correlation with variables related to primary muscle damage than to secondary muscle damage, suggesting that cfDNA is a more sensitive marker of acute loss of muscle function than of secondary inflammation or damaged muscle fibres. What is the central question of this study? How do plasma cell‐free DNA (cfDNA) levels change in response to primary and secondary muscle damage when muscle‐damaging exercise is performed without metabolic stress? What is the main finding and its importance? In this study, we found that cfDNA concentration increases following severe primary and secondary muscle damage after 50 drop jumps. However, acute postexercise increases in cfDNA were higher than following secondary muscle damage and were more correlated with variables related to primary muscle damage (low‐frequency fatigue). This suggests that muscle‐damaging exercise causing no accumulation of metabolites can lead to acute and delayed increases in cfDNA levels. However, they are more sensitive to primary muscle damage.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: Adult / Biomarkers - blood / blood markers / Cell-Free Nucleic Acids - blood / cell‐free DNA / Creatine / Creatine kinase / Creatine Kinase - blood / DNA damage / eccentric exercise / Exercise - physiology / Fatigue / Humans / Isometric Contraction - physiology / Kinetics / Male / Muscle contraction / muscle damage / Muscle Fatigue - physiology / Muscle, Skeletal - injuries / Muscle, Skeletal - metabolism / Myalgia - physiopathology / Torque / Young Adult