Apoptosis Regulation in Dental Pulp Cells and PD-1/PD-L1 Expression Dynamics Under Ozone Exposure - A Pilot Approach

Area of Science:

• Dental Pulp Biology
• Oxidative Stress Research
• Immunology

Background:

• Dental pulp cells are crucial for tooth vitality and repair.
• Ozone therapy is used in dentistry, but its cellular effects require further investigation.
• Understanding cellular responses to oxidative stress is key to managing dental pulp health.

Purpose of the Study:

• To investigate the impact of ozone on the expression of pro-apoptotic (Bax) and anti-apoptotic (Bcl-2) genes in dental pulp stromal cells.
• To assess the surface expression of immune checkpoint molecules programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and CD200/CD200R on lymphocytes after ozone exposure.

Main Methods:

• Dental pulp stromal cells were cultured and exposed to ozone for 0, 6, and 12 seconds.
• Real-time PCR was used to analyze Bax and Bcl-2 gene expression.
• Flow cytometry was employed to measure PD-1, PD-L1, and CD200/CD200R expression on lymphocytes after 12 seconds of ozone exposure.

Main Results:

• Ozone exposure at 6 seconds significantly decreased Bcl-2 expression and increased Bax expression.
• At 12 seconds of ozone exposure, Bcl-2 expression significantly increased, while Bax expression remained elevated.
• Lymphocytes exposed to ozone for 12 seconds exhibited minimal changes in PD-1, PD-L1, and CD200/CD200R expression.

Conclusions:

• Ozone exposure influences the balance between apoptosis and cell survival in dental pulp cells, with prolonged exposure potentially favoring survival.
• The observed changes suggest dental pulp cells attempt to counteract prolonged oxidative stress.
• Immune checkpoint molecules PD-1, PD-L1, and CD200/CD200R on lymphocytes appear resistant to short-term ozone-induced oxidative stress in this context.