A 50 kdyne contusion spinal cord injury with or without the drug SS-31 was not associated with major changes in muscle mass or gene expression 14 d after injury in young male mice

Physiological Reports, 2021 · DOI: 10.14814/phy2.14751 · Published: January 12, 2021

Spinal Cord Injury Genetics Musculoskeletal Medicine

Simple Explanation

This study investigated the potential of SS-31, a mitochondrial-targeting peptide, to prevent muscle loss following spinal cord injury (SCI) in mice. SCI often leads to rapid muscle atrophy due to paralysis and disuse. The researchers hypothesized that SS-31 could preserve muscle mass in mice with SCI. However, the results showed that SS-31 did not have a significant protective effect on muscle or body mass after SCI in this model. The study suggests that the specific SCI model used, a 50 kdyne contusion, may not induce substantial muscle atrophy, and any potential benefits of SS-31 might be overshadowed by natural recovery processes.

Study Duration

14 d

Participants

Male C57BL/6 mice aged 9 weeks

Evidence Level

Not specified

Key Findings

1
A 50 kdyne contusion SCI in young male mice resulted in decreased body mass and loss of mass in plantaris and gastrocnemius muscles.
2
SS-31 administration did not protect against SCI-related changes in body or muscle mass, protein synthesis, or protein carbonylation.
3
SS-31 was associated with alterations in the mRNA expression profile of myosin heavy chains, specifically MYH7 and MYH2.

Research Summary

This study aimed to determine if SS-31, a mitochondrial-targeting peptide, could prevent muscle loss after SCI in mice. A 50 kdyne contusion SCI model was used, and mice were administered daily injections of SS-31 or vehicle for 14 days. The results showed that SCI led to decreased body mass and loss of mass in certain muscles, but SS-31 did not provide a protective effect. There were no significant changes in protein synthesis or protein carbonylation. The study concludes that SS-31 does not seem to be an efficacious therapy for preventing body or muscle mass losses after a 50 kdyne contusion SCI in mice, and the specific SCI model used may not induce sustained muscle atrophy.

Practical Implications

Limited Efficacy of SS-31 in SCI Model

SS-31 may not be effective in preventing muscle atrophy in this specific contusion SCI model.

Importance of SCI Model Selection

The severity and type of SCI model significantly influence the extent of muscle atrophy and the potential benefits of interventions.

Potential Alterations in Myosin Expression

SS-31 might have a role in modulating myosin heavy chain expression, warranting further investigation.

Study Limitations

1
The animals recovered some locomotor function, potentially missing the therapeutic window for SS-31.
2
Respiratory or contractile function was not measured.
3
The effect of SS-31 on mitochondrial enzymatic function or ROS production was not assessed.

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