Finite element analysis on mechanical state on the osteoclasts under gradient fluid shear stress

Area of Science:

• Biomechanics
• Cell Biology
• Biomaterials

Background:

• Mechanical loading, specifically fluid shear stress (FSS), is a key regulator of bone cell biological responses.
• Previous studies showed RAW264.7 osteoclast precursors migrate towards low-FSS regions in a gradient FSS field.
• The dependence of FSS distribution on the gradient direction requires clarification to explain observed cell migration patterns.

Purpose of the Study:

• To clarify how FSS distribution on a cell is influenced by the FSS gradient direction.
• To investigate the relationship between FSS distribution and osteoclast precursor migration.
• To explain the experimental observation of cell migration towards low-FSS regions.

Main Methods:

• Construction of finite element models for discretely distributed and closely packed cells.
• Modeling cells as compressible isotropic Hookean solids.
• Analysis of FSS distribution in different cell arrangements and orientations within a cone-and-plate flow chamber.

Main Results:

• Discretely distributed cells experienced approximately 0.1% greater average FSS in the sector far from the center (SFC) compared to the sector near the center (SNC).
• The relative FSS difference between SFC and SNC decreased with increasing band height for individual cells.
• For hexagonal packed cells, the SFC to SNC FSS ratio increased with greater cell spacing.

Conclusions:

• The calculated FSS differences between the SFC and SNC regions of cells are significant.
• These FSS variations may activate mechanosensitive ion channels.
• This mechanism provides a potential explanation for the directed migration of osteoclast precursors towards low-FSS environments.