In vitro system for applying cyclic loads to connective tissues under displacement or force control

Area of Science:

• Biomedical Engineering
• Orthopedics
• Tissue Engineering

Background:

• Overuse is a primary cause of chronic tendon injuries due to repetitive loading.
• This leads to micro-tears and maladaptive repair responses in connective tissues.
• In vitro organ culture models are crucial for studying cellular responses to load.

Purpose of the Study:

• To develop and validate a novel tissue loading system for in vitro studies.
• To investigate the relationship between loading parameters and biomechanical factors in connective tissues.
• To elucidate early mechanisms of tendinopathies and ligament injuries.

Main Methods:

• Designed a novel tissue loading system with closed-loop force feedback.
• Enabled independent loading of six tissue samples under force or displacement control.
• System capable of applying loads up to 40 N at rates of 100 N/s and frequencies of 2 Hz.

Main Results:

• The system allows precise control over loading parameters (amplitude, rate, frequency).
• Biomechanical factors like creep, force relaxation, and modulus can be assessed.
• Loading parameters exceed those measured in rabbit tendons in vivo.

Conclusions:

• The novel system facilitates detailed examination of connective tissue responses to mechanical loading.
• Provides valuable insights into the etiology of overuse injuries.
• Supports research into tendinopathies and ligament injuries.