Insights Into Transcriptional Dynamics of Tissue-Engineered Contractile Human Skeletal Muscle in Response to Electrical Pulse Stimulation

Background: The in vitro human skeletal muscle model is a valuable tool for studying muscle physiology and mechanisms underlying muscle diseases. Our previous work demonstrated that a tissue-engineering approach could produce contractile human muscle tissue, with electrical pulse stimulation (EPS) enhancing its contractility. However, challenges remain in achieving maturation levels that closely mimic native muscles. Methods: We performed contractility analysis and mRNA sequencing of muscle tissues subjected to different EPS-induced exercise protocols and antioxidant supplementation. Results: Although an appropriate amount of EPS enhanced contractility, excessive EPS caused tissue damage and reduced functionality. Both types of EPS promoted extracellular matrix reconstitution, skeletal muscle tissue development, oxidative stress response, and myokine production. However, specific genes, including ACTN3, were differentially expressed. EPS also led to hydrogen peroxide accumulation in the medium. The contractility assays and transcriptomic profiles suggested that the negative effects of accumulated hydrogen peroxide were mitigated by catalase supplementation. Although catalase effectively degraded extracellular hydrogen peroxide, transcriptomic data indicated that the intracellular oxidative stress caused by excessive EPS still negatively affected tissue maturation. Conclusion: These findings highlight the need to optimize EPS-induced exercise protocols, balancing extracellular and intracellular oxidative stress to improve the maturation of in vitro muscle tissue.