Tissue strain amplification at the osteocyte lacuna: a microstructural finite element analysis

Area of Science:

• Biomechanical Engineering
• Cellular Mechanobiology
• Bone Tissue Mechanics

Background:

• Osteocyte lacunae are critical cellular components within bone tissue.
• Understanding their response to mechanical loading is vital for bone health and disease research.
• Previous models have simplified the complex microenvironment surrounding osteocytes.

Purpose of the Study:

• To develop a parametric finite element model of an osteocyte lacuna.
• To predict the microstructural response of the lacuna to macroscopic strains.
• To investigate the influence of canalicular dimensions and perilacunar tissue properties on strain distribution.

Main Methods:

• A parametric finite element model was constructed, incorporating the osteocyte lacuna, perilacunar tissue, canaliculi, and surrounding bone.
• 45 simulations were performed, varying canalicular diameter, perilacunar tissue modulus, and perilacunar tissue thickness.
• Macroscopic strains were applied to simulate in vivo loading conditions.

Main Results:

• Maximum strain increased with decreased perilacunar tissue modulus and increased with larger canalicular diameters.
• Canalicular diameters showed a notable increase (0.8%–1.0%) under strain, influenced by perilacunar tissue modulus.
• Strain magnification factors exceeding 3 were predicted, with perilacunar tissue thickness having no significant effect on local strain.
• Lower perilacunar tissue modulus amplified perilacunar tissue strain and canaliculi deformation.

Conclusions:

• In vivo macroscopic strains can lead to significantly amplified perilacunar tissue strains and canaliculi deformations.
• Perilacunar tissue modulus is a key determinant of osteocyte lacunae mechanotransduction.
• These findings highlight the importance of local tissue properties in bone's response to mechanical stimuli.