Applying Physiologically Relevant Strains to Tenocytes in an In Vitro Cell Device Induces In Vivo Like Behaviors

Area of Science:

• Biomedical Engineering
• Cell Biology
• Biomaterials Science

Background:

• Tenocytes, crucial for tendon health, respond to mechanical stimuli.
• Previous in vitro studies often used non-physiological strain magnitudes.
• Accurate mechanical stimulation is vital for understanding tenocyte behavior and tissue regeneration.

Purpose of the Study:

• To develop and validate a novel cell stretching device (Cell Gym) for applying physiologically relevant low strains to tenocytes.
• To assess the device's accuracy in transferring substrate strain to cells.
• To investigate the effects of mechanical stimulation on tenocyte gene expression and collagen synthesis.

Main Methods:

• Development of the Cell Gym device for controlled mechanical strain application.
• Validation of strain transfer from substrate to tenocytes (∼90% accuracy).
• Analysis of gene expression (COL I, COX2) and collagen synthesis in mechanically stimulated tenocytes.

Main Results:

• Mechanically stimulated tenocytes (4% strain) showed reduced COL I gene expression.
• COX2 gene expression increased, though not statistically significant.
• The device reproduced in vivo findings of collagen synthesis peaking 24 hours post-exercise.

Conclusions:

• Physiologically relevant low strain magnitudes are critical for in vitro cell mechanical studies.
• Thorough device validation is essential for accurate mechanical stimulation at small strains.
• The Cell Gym device shows promise for designing future tendon tissue engineering scaffolds.