Low amplitude characterization tests conducted at regular intervals can affect tendon mechanobiological response

Area of Science:

• Tissue engineering
• Mechanobiology
• Bioreactor technology

Background:

• Characterizing tissue quality in bioreactors is crucial for understanding mechanical stimuli responses.
• Current methods are often destructive, preventing longitudinal studies on the same sample.
• Non-destructive methods like stress relaxation tests face a dilemma: measurement interference with live tissue progression.

Purpose of the Study:

• To investigate if regular stress relaxation tests at physiological amplitudes affect tissue progression during bioreactor culture.
• To determine if these tests alter the response of live tissues to mechanical stimulation over time.

Main Methods:

• Live, healthy tendons were cultured in a bioreactor for 3 days under mechanical stimulation.
• Tendons were divided into groups based on daily stress relaxation test frequency (24 or 0 tests).
• Mechanical and histological analyses were performed to compare tissue progression between groups.

Main Results:

• Stress relaxation tests at physiological amplitudes significantly modified the tendon's response to mechanical stimulation.
• Both mechanical properties and histological outcomes differed between groups subjected to regular testing and those without.
• The testing protocol itself influenced the biological response being measured.

Conclusions:

• Regular stress relaxation tests can interfere with the assessment of tissue progression in bioreactor studies.
• Minimizing the frequency of stress relaxation tests or utilizing the mechanical stimulation itself for characterization are potential solutions.
• Further research is needed to refine non-destructive assessment methods in mechanobiology.