Antioxidants (Jun 2024)

Electrical Pulse Stimulation Protects C2C12 Myotubes against Hydrogen Peroxide-Induced Cytotoxicity via Nrf2/Antioxidant Pathway

  • Sarah Pribil Pardun,
  • Anjali Bhat,
  • Cody P. Anderson,
  • Michael F. Allen,
  • Will Bruening,
  • Joel Jacob,
  • Ved Vasishtha Pendyala,
  • Li Yu,
  • Taylor Bruett,
  • Matthew C. Zimmerman,
  • Song-Young Park,
  • Irving H. Zucker,
  • Lie Gao

DOI
https://doi.org/10.3390/antiox13060716
Journal volume & issue
Vol. 13, no. 6
p. 716

Abstract

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Skeletal muscle contraction evokes numerous biochemical alterations that underpin exercise benefits. This present study aimed to elucidate the mechanism for electrical pulse stimulation (EPS)-induced antioxidant adaptation in C2C12 myotubes. We found that EPS significantly upregulated Nrf2 and a broad array of downstream antioxidant enzymes involved in multiple antioxidant systems. These effects were completely abolished by pretreatment with a ROS scavenger, N-acetylcysteine. MitoSOX-Red, CM-H2DCFDA, and EPR spectroscopy revealed a significantly higher ROS level in mitochondria and cytosol in EPS cells compared to non-stimulated cells. Seahorse and Oroboros revealed that EPS significantly increased the maximal mitochondrial oxygen consumption rate, along with an upregulated protein expression of mitochondrial complexes I/V, mitofusin-1, and mitochondrial fission factor. A post-stimulation time-course experiment demonstrated that upregulated NQO1 and GSTA2 last at least 24 h following the cessation of EPS, whereas elevated ROS declines immediately. These findings suggest an antioxidant preconditioning effect in the EPS cells. A cell viability study suggested that the EPS cells displayed 11- and 36-fold higher survival rates compared to the control cells in response to 2 and 4 mM H2O2 treatment, respectively. In summary, we found that EPS upregulated a large group of antioxidant enzymes in C2C12 myotubes via a contraction-mitochondrial-ROS-Nrf2 pathway. This antioxidant adaptation protects cells against oxidative stress-associated cytotoxicity.

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