Optimization of Xenografting Methods for Generating Human Skeletal Muscle in Mice

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Muscle Physiology

Background:

• Human skeletal muscle xenografts in mice are valuable models for studying muscle diseases and drug efficacy.
• Previous methods established generating mature human muscle from human myogenic precursor cells (hMPCs).

Purpose of the Study:

• To optimize the engraftment and robustness of human skeletal muscle xenografts in mice.
• To identify alternative treatments and conditions for improved xenograft generation.

Main Methods:

• Examined various factors including X-irradiation dose, hMPC line variability, neuromuscular electrical stimulation (iNMES), sex differences, and biomaterial coinjections.
• Tested alternative toxins for muscle ablation, comparing BaCl2, snake venom, and cardiotoxin.
• Compared graft generation methods using iNMES versus running wheels.

Main Results:

• 25Gy X-irradiation is optimal for murine muscle ablation, supporting human fiber formation without contamination.
• Significant variability exists in hMPC engraftment capacity and response to iNMES.
• BaCl2 serves as an effective replacement for cardiotoxin; coinjection with biomaterials does not enhance engraftment.
• Engrafting both hindlimbs and applying iNMES results in more robust grafts compared to running wheels.

Conclusions:

• Replacing cardiotoxin with BaCl2 and utilizing bilateral tibialis anterior muscle engraftment optimizes the generation of robust adult human skeletal muscle xenografts in mice.
• These optimized xenografts provide a more reliable model for studying muscle pathology and therapeutic interventions.