Mouse study: chronic mitochondrial redox stress shifts acute muscle-contraction signaling
In mice, 12 weeks of induced SOD2 knockdown in skeletal muscle changed the signaling response to a single acute fatiguing contraction: metabolic pathways were not activated, while oxidative stress, apoptosis and inflammation pathways were. [1]
Automatic summary · not editorially reviewed
The key findings
After 12 weeks of doxycycline treatment to knock down SOD2, knockdown mice and littermate controls underwent a single acute fatiguing contraction of the right hindlimb. [1]
Knockdown increased reversible thiol oxidation of mitochondrial proteins after contraction and reduced several key iron-sulfur cluster biosynthesis proteins. [1]
Contraction activated insulin, glucose metabolism, calcium and energy stress signaling in controls but not in knockdown muscle, which instead activated apoptosis, oxidative stress and inflammatory pathways. [1]
The source at a glance
- Study type / format
- Preclinical mouse study (abstract)
- Population / context
- Mice with inducible SOD2 knockdown in skeletal muscle and littermate controls.
- Summary based on
- Study abstract
- Original publication
- October 7, 2026
Induced SOD2 knockdown before one acute contraction
The researchers used a new mouse model in which superoxide dismutase 2 (SOD2) can be switched down in skeletal muscle (iSOD2 KD). After 12 weeks of doxycycline treatment to knock down SOD2, these mice and littermate controls received a single acute fatiguing contractile stimulus of the right hindlimb. Muscle was collected immediately after or 3 hours after the stimulus and compared with unstimulated controls of each genotype. The question was how long-lasting changes in mitochondrial redox balance affect the signaling response to a later contraction.
Supporting source [1]
Altered redox proteins and pathway activation in knockdown mice
The knockdown lowered protein levels of several key proteins for building iron-sulfur clusters. After contraction, reversible thiol oxidation of proteins in the mitochondrial compartment increased. In the transcriptomic response to contraction, knockdown muscle showed activation of apoptosis, oxidative stress and inflammatory pathways, while controls showed no significant perturbation. Controls activated insulin signaling and glucose metabolism, calcium signaling and energy stress signaling; knockdown muscle did not. The authors interpret this as a shift away from metabolic signaling toward oxidative stress and apoptotic signaling, which may become pathological or maladaptive over time.
Supporting source [1]
Mouse-only scope; long-term consequences not tested
This is an abstract of a mouse study; the full text was not reviewed. The design compares a single acute contraction in knockdown versus control mice, with tissue taken immediately or 3 hours afterward, so it does not show effects on long-term exercise adaptation, human muscle or lifespan. The suggestion that signaling may become pathological or maladaptive over time is the authors' interpretation, not a measured outcome. Associations between the redox change and pathway activation do not establish causation in humans.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. Findings come from mice with induced SOD2 knockdown and a single acute contraction, with tissue collected immediately or 3 hours later. Long-term adaptation, human relevance and lifespan effects were not measured.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Ostrom EL, Mattson-Hughes A, MacDonald J, Bammler T, Day NJ, Gaffrey MJ, Trejo JB, Qian WJ, Hagy B, Giorgione JR, Humphries KM, Van Remmen H, Rodriguez-Mias R, Villen J, Marcinek DJ. · europepmc.org · October 7, 2026