Effects of tissue preservation on murine bone mechanical properties

Area of Science:

• Orthopedics
• Biomaterials Science
• Skeletal Biology

Background:

• Mechanical testing of murine bone is crucial for skeletal research.
• Specimen preservation is necessary due to the destructive nature of mechanical testing.
• Understanding preservation effects on bone mechanics is vital.

Purpose of the Study:

• To investigate the impact of freezing and formalin fixation on murine femur and vertebrae mechanical properties.
• To compare the elastic and viscoelastic properties of preserved versus fresh bone specimens.
• To determine optimal preservation methods for skeletal research.

Main Methods:

• 120 femurs and 180 vertebrae underwent non-destructive cyclic loading and monotonic loading to failure.
• Specimens were preserved via freezing or formalin fixation.
• All specimens were re-hydrated in 0.9% saline for 30 minutes prior to testing.

Main Results:

• Freezing and formalin fixation did not alter elastic properties (stiffness, modulus, yield, ultimate load/strength).
• Freezing did not affect viscoelastic properties (loss, storage, dynamic moduli).
• Formalin fixation negatively impacted viscoelastic properties, reducing energy dissipation.

Conclusions:

• Short-term (2-week) freezing or formalin fixation preserves elastic mechanical properties of murine bone.
• Re-hydration for 30 minutes is essential before testing preserved specimens.
• Formalin fixation compromises murine bone's viscoelasticity, impacting energy dissipation capabilities.