Characterization and utilization of the flexor digitorum brevis for assessing skeletal muscle function

Area of Science:

• Skeletal muscle physiology and function
• Mitochondrial respiration and bioenergetics
• Molecular mechanisms of muscle regulation

Background:

• Skeletal muscle research faces challenges due to variations in fiber type and size across different muscles.
• The flexor digitorum brevis (FDB) muscle presents unique properties offering significant experimental flexibility.
• Few studies have leveraged the FDB muscle for investigating skeletal muscle regulatory mechanisms.

Purpose of the Study:

• To characterize the phenotype of the FDB muscle.
• To compare the FDB muscle with commonly used skeletal muscles in research.
• To demonstrate the experimental versatility and value of the FDB muscle for scientific investigations.

Main Methods:

• Characterization of FDB muscle phenotype and comparison with other skeletal muscles.
• Development of methods for assessing force production, in vitro/in vivo microscopy, and mitochondrial respiration.
• Experimental validation of FDB muscle flexibility through manipulation of force production and mitochondrial respiration.

Main Results:

• The FDB muscle comprises small, predominantly type IIa and IIx fibers, exhibiting greater fatigue resistance than the extensor digitorum longus (EDL).
• The FDB muscle is amenable to various in vitro and in vivo microscopy techniques, cardiotoxin-induced injury protocols, and efficient genetic manipulation via electroporation.
• Novel methods for assessing mitochondrial respiration in the FDB muscle were established, comparable to those in the gastrocnemius muscle, with Pgc1α overexpression increasing respiration rates.

Conclusions:

• The FDB muscle provides significant experimental flexibility for researchers.
• Its unique properties facilitate the investigation of mechanisms regulating skeletal muscle function.
• The FDB muscle serves as a valuable model for uncovering therapeutic strategies for muscle-related diseases.