Experimental autoimmune encephalomyelitis causes skeletal muscle dysfunction in mice.

Area of Science:

• Neuroimmunology
• Skeletal Muscle Physiology

Background:

• Multiple sclerosis (MS) is a neuroinflammatory disease causing demyelination and chronic inflammation, leading to significant peripheral muscle dysfunction and mobility decline in over 90% of patients.
• Current MS treatments primarily target inflammation and do not halt disease progression or specifically address muscle dysfunction, highlighting an unmet need for novel therapeutic strategies.
• Developing effective treatments for skeletal muscle dysfunction in MS requires reliable preclinical models that accurately replicate human musculoskeletal manifestations.

Purpose of the Study:

• To establish and validate a non-invasive in vivo preclinical model for assessing skeletal muscle function in Experimental Autoimmune Encephalomyelitis (EAE), a model for multiple sclerosis (MS).
• To investigate the impact of EAE on skeletal muscle strength and contractile properties.
• To provide a foundation for preclinical drug candidate profiling aimed at improving muscle function in MS patients.

Main Methods:

• Utilized a non-invasive in vivo approach involving direct transcutaneous muscle stimulation in anesthetized mice to assess skeletal muscle function.
• Measured electrically evoked tetanic muscle contractions at short intervals (0.25 s) to mimic fatiguing conditions.
• Employed repeated evaluations of muscle function, controlling for primary fatigue and reduced nerve input.

Main Results:

• Animals with EAE exhibited significantly lower muscle force (28.3%, p < 0.0001) compared to healthy control mice during tetanic contractions.
• The experimental setup allowed for repeated, reliable measurements of muscle function without confounding factors like primary fatigue or nerve input reduction.
• Demonstrated that EAE impairs skeletal muscle strength, showing contractile impairments similar to those observed in human MS patients.

Conclusions:

• The EAE model effectively mimics skeletal muscle contractile impairments seen in human multiple sclerosis.
• The developed non-invasive in vivo setup provides a valuable tool for the preclinical assessment of novel therapeutic candidates targeting muscle dysfunction in MS.
• This research supports the development of targeted treatments to improve muscle function and mobility in individuals with multiple sclerosis.