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Updated: Feb 22, 2026
Biomechanical Testing of Murine Tendons
Published on: October 15, 2019
Optimizing a 3D model system for molecular manipulation of tenogenesis
Chun Chien1, Brian Pryce2, Sara F Tufa2
1a Department of Orthopaedics , Icahn School of Medicine at Mount Sinai , New York , NY , USA.
Purpose:
Tendon injuries are clinically challenging due to poor healing. A better understanding of the molecular events that regulate tendon differentiation would improve current strategies for repair. The mouse model system has been instrumental to tendon studies and several key molecules were initially established in mouse. However, the study of gene function has been limited by the absence of a standard in vitro tendon system for efficiently testing multiple mutations, physical manipulations, and mis-expression. The purpose of this study is therefore to establish such a system.
Methods:
We adapted an existing design for generating three-dimensional (3D) tendon constructs for use with mouse progenitor cells harboring the ScxGFP tendon reporter and the Rosa26-TdTomato Cre reporter. Using these cells, we optimized the parameters for construct formation, inducing tenogenesis via transforming growth factor-β2 (TGFβ2), and genetic recombination via an adenovirus encoding Cre recombinase. Finally, for proof of concept, we used Smad4 floxed cells and tested the robustness of the system for gene knockdown.
Results:
We found that TGFβ2 treatment induced a tenogenic phenotype depending on the timing of initiation. Addition of TGFβ2 after 3D "tensioning" enhanced tendon differentiation. Interestingly, while TGFβ2-induced proliferation depended on Smad4, tenogenic parameters such as ScxGFP expression and fibril diameter were independent of Smad4.
Conclusions:
Our results demonstrate the feasibility of this optimized system for harnessing the power of mouse genetics for in vitro applications.
Insights
Researchers developed a new 3D in vitro tendon model using mouse cells. This system efficiently tests gene function and physical manipulations, advancing tendon repair research.
Area of Science:
- Biomaterials Science
- Molecular Biology
- Regenerative Medicine
Background:
- Tendon injuries exhibit poor healing, necessitating improved repair strategies.
- Understanding molecular regulation of tendon differentiation is key to enhancing repair.
- Mouse models have identified crucial tendon molecules, but in vitro functional studies are limited.
Purpose of the Study:
- Establish a robust 3D in vitro tendon model using mouse progenitor cells.
- Optimize parameters for construct formation, tenogenesis induction, and genetic manipulation.
- Create a system for efficient in vitro testing of gene function in tendon development.
Main Methods:
- Adapted a 3D construct design for mouse progenitor cells with ScxGFP and Rosa26-TdTomato reporters.
- Optimized tenogenesis using transforming growth factor-beta2 (TGFβ2).
- Utilized adenovirus encoding Cre recombinase for genetic recombination and Smad4 floxed cells for gene knockdown validation.
Main Results:
- TGFβ2 treatment timing influenced tenogenic phenotype induction, with post-tensioning addition enhancing differentiation.
- TGFβ2-induced proliferation was Smad4-dependent.
- Key tenogenic parameters, including ScxGFP expression and fibril diameter, were Smad4-independent.
Conclusions:
- Demonstrated the feasibility of an optimized 3D in vitro system for tendon research.
- The system effectively harnesses mouse genetics for in vitro applications.
- Provides a powerful tool for studying tendon differentiation and repair mechanisms.
