Dynamic Loading Does Not Interfere With the Initial Repopulation of Decellularized Tendons: An Ex Vivo Study

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Tissue Engineering

Background:

• Anterior cruciate ligament (ACL) rupture causes joint instability, often treated with tendon autografts.
• Implanted autografts contain non-viable cells, potentially leading to inflammation and graft failure.
• Decellularized grafts offer an alternative, but cell repopulation under dynamic loading is unclear.

Purpose of the Study:

• To investigate the repopulation efficiency of decellularized tendons with fibroblasts under dynamic loading.
• To evaluate cell viability, adhesion, metabolism, and infiltration in response to mechanical stimulation.
• To assess the utility of a custom bioreactor as a model for ACL graft research.

Main Methods:

• Human gracilis tendons were decellularized and reseeded with human dermal fibroblasts.
• Cells were cultured dynamically (2%-6% strain at 1Hz for 7h/day) or statically for 7 days.
• A custom bioreactor was used to apply dynamic loading and assess mechanical properties and cell behavior.

Main Results:

• The bioreactor successfully measured transient mechanical responses and property changes over time.
• Dynamic loading did not significantly affect cell adhesion, viability, metabolism, or infiltration.
• Cell infiltration was localized in both static and dynamic groups, not globally distributed.

Conclusions:

• Dynamic loading conditions do not negatively impact cell behavior in reseeded decellularized tendons.
• The developed bioreactor shows potential as an in vitro/ex vivo model for predicting in vivo ACL graft outcomes.
• Further research using this model could advance the development of improved ACL grafts.