Compressive force induces osteoblast apoptosis via caspase-8

Area of Science:

• Biomedical Engineering
• Cell Biology
• Orthodontics

Background:

• Periodontal remodeling is essential for orthodontic tooth movement.
• Excessive orthodontic forces can lead to cell death in periodontal tissues.
• The specific mechanisms of cell death induced by compressive forces are not fully understood.

Purpose of the Study:

• To investigate whether continuous compressive force induces apoptosis in human osteoblast-like cells (MG-63 cells) in vitro.
• To elucidate the signaling pathway involved in compressive force-induced apoptosis.

Main Methods:

• Application of continuous compressive force to MG-63 cells in vitro.
• Assessment of cell viability and morphology.
• TUNEL assay to quantify apoptosis.
• Measurement of caspase-3 activity and evaluation of inhibitor effects (caspase-8 and caspase-9 inhibitors).

Main Results:

• Compressive force caused irregular cell alignment and decreased cell viability.
• TUNEL analysis revealed a time- and force-dependent increase in apoptotic cells.
• Caspase-3 activity increased with compressive force magnitude.
• Caspase-8 inhibition significantly reduced caspase-3 activity, while caspase-9 inhibition had no effect.

Conclusions:

• In vitro application of compressive force induces apoptosis in MG-63 cells.
• Apoptosis is mediated through the activation of caspase-3 via the caspase-8 signaling cascade.
• Findings provide insights into the cellular mechanisms underlying orthodontic force-induced tissue remodeling and potential cell death.