Tissue Engineered Scaffolds Combined with Exercise in the Treatment of Volumetric Muscle Loss in Rat Model

Nanoscience Chemistry Materials Science Bioengineering Sports Medicine Life Sciences Medicine
Volumetric Muscle Loss Polycaprolactone Silver Nanoparticle Decellularized Human Amniotic Membrane Exercise

Academic Background

Volumetric Muscle Loss (VML) is a severe muscle injury typically caused by trauma, ischemia, or tumor excision. VML leads to irreversible loss of muscle fibers, resulting in fibrosis, deformity, and long-term dysfunction. Unlike ordinary muscle injuries, VML has very limited regenerative capacity because the extent of damage exceeds the muscle’s self-repair ability. Traditional treatments, such as physical therapy and cell transplantation, have limited effectiveness and cannot fully restore muscle function. Therefore, Tissue Engineering (TE) techniques have emerged as a promising approach to address VML. By using natural or synthetic biomaterials, TE scaffolds can provide structural support to damaged tissues, promote vascularization and nerve regeneration, and thus facilitate the regeneration of functional tissue.

This study aims to explore a novel TE scaffold—a Polycaprolactone (PCL) scaffold combined with Silver Nanoparticles (AgNPs) and a Decellularized Human Amniotic Membrane (HAM) scaffold, combined with forced exercise training, to treat VML in a rat model. The research hopes that this combination therapy will promote vascularization, nerve regeneration, and myofiber regeneration, thereby improving muscle function.

Source of the Paper

This paper was co-authored by Maryam Zohour Soleimani, Fereshteh Nejaddehbashi, Mahmoud Orazizadeh, Seyed Esmaeil Khoshnam, and Vahid Bayati. The authors are affiliated with the Department of Anatomical Sciences, the Cellular and Molecular Research Center (CMRC), and the Persian Gulf Physiology Research Center at Ahvaz Jundishapur University of Medical Sciences in Iran. The paper was accepted on March 31, 2025, and published in the journal Bionanoscience with the DOI 10.1007/s12668-025-01921-7.

Research Process

1. Materials and Scaffold Preparation

The study first prepared two types of scaffolds: PCL/Ag (Polycaprolactone/Silver Nanoparticles) and PCL/HAM/Ag (Polycaprolactone/Decellularized Human Amniotic Membrane/Silver Nanoparticles).
- Synthesis of Silver Nanoparticles: AgNPs were synthesized through chemical reduction, and their size and morphology were characterized using Transmission Electron Microscopy (TEM).
- Preparation of Decellularized Human Amniotic Membrane: Human amniotic membranes were obtained from cesarean sections, subjected to multiple freeze-thaw cycles and enzymatic treatments to remove cellular components, retaining the Extracellular Matrix (ECM).
- Scaffold Preparation: PCL/Ag nanofibers were prepared using electrospinning and combined with HAM to form PCL/HAM/Ag composite scaffolds.

2. Scaffold Characterization

Scanning Electron Microscopy (SEM) and Field Emission SEM (FE-SEM) were used to observe the microstructure and fiber alignment of the scaffolds. Tensile tests were conducted to evaluate the mechanical properties, and the presence of AgNPs was verified using Energy-Dispersive X-ray Spectroscopy (EDX).

3. Antibacterial Performance Testing

The study evaluated the antibacterial effects of the scaffolds against Escherichia coli and Staphylococcus aureus by measuring the inhibition zones to determine their antibacterial activity.

4. Cell Experiments

  • Cell Adhesion and Proliferation: Human Embryonic Kidney cells (HEK 293) were seeded onto the scaffolds, and cell viability and proliferation were assessed using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.
  • Cell Migration Experiment: The effects of scaffold extracts on cell migration were evaluated using the Scratch Test.

5. Animal Experiments

  • Establishment of the VML Model: A 30% VML injury was created in the left Tibialis Anterior (TA) muscle of 8-week-old Wistar rats.
  • Scaffold Transplantation: PCL/Ag and PCL/HAM/Ag scaffolds were transplanted into the injury site, followed by forced treadmill training post-surgery.
  • Functional Assessment: Motor function recovery was observed through the Open Field Test and Walking Behavior Assessment.
  • Histological Analysis: Tissue samples were collected at 7, 14, and 28 days post-surgery for Hematoxylin & Eosin (H&E) staining, Masson’s trichrome staining, and immunohistochemical staining (Desmin staining) to evaluate muscle regeneration and vascularization.

Main Results

  1. Scaffold Characterization: Both PCL/Ag and PCL/HAM/Ag scaffolds exhibited good fiber alignment and mechanical properties, with the addition of HAM significantly enhancing the mechanical stability of the scaffolds.
  2. Antibacterial Performance: Both scaffolds showed significant antibacterial activity against Staphylococcus aureus and Escherichia coli, with stronger inhibition against Staphylococcus aureus.
  3. Cell Experiments: The PCL/Ag scaffold outperformed the PCL/HAM/Ag scaffold in cell adhesion and proliferation, indicating its suitability for cell growth.
  4. Animal Experiments: At 28 days post-surgery, both PCL/Ag and PCL/HAM/Ag scaffolds promoted muscle regeneration and vascularization, and rats subjected to forced exercise training showed significant motor function recovery.

Conclusion

This study is the first to combine AgNPs with PCL/HAM scaffolds for the treatment of VML injuries. The results demonstrate that PCL/Ag and PCL/HAM/Ag scaffolds combined with forced exercise training can effectively promote muscle regeneration, vascularization, and nerve regeneration, thereby improving muscle function. This finding provides a new approach for VML treatment, with significant scientific and practical value.

Research Highlights

  1. Innovative Scaffold Design: The first combination of AgNPs with PCL/HAM scaffolds enhances the antibacterial properties and mechanical stability of the scaffolds.
  2. Comprehensive Therapy: The combination of TE scaffolds with forced exercise training significantly improves muscle function recovery.
  3. Multidimensional Evaluation: The therapeutic effects of the scaffolds were comprehensively evaluated through cell experiments, animal experiments, and histological analysis.

Significance and Value

This study provides a new comprehensive therapy for VML treatment, demonstrating the potential of TE scaffolds combined with exercise training. This approach not only promotes muscle regeneration but also improves patients’ motor function, holding significant clinical application prospects. Future research can further optimize scaffold design, extend implantation time, and explore more functional assessment methods to validate its long-term efficacy.