Effect of Compressive Force on the Production of Prostaglandin E₂ and its Receptors in Osteoblastic Saos-2 Cells

Abstract

In orthodontic tooth movement, prostaglandin E₂ (PGE₂) released from osteoblasts can alter the normal process of bone remodeling. We examined the effect of compressive force (CF) on PGE₂ production, PGE receptors (Ep1–4) expression, phosphorylation of protein kinase A (p-PKA), and calcium content in Saos-2 cells. PGE₂ production increased as CF strength. Applying CF of 98 or 294 Pa caused the cells to produce approximately 700 and 1400 pg/mL PGE₂, respectively. CF of 98 Pa increased Ep2 gene expression, and 98 and 294 Pa CF increased Ep4. Immunohistochemical staining showed strong expression of Ep2 under 98 Pa and Ep4 under 98 and 294 Pa. The p-PKA increased as the strength of CF or PGE₂ concentration. The calcium content was increased by the addition of 700 pg/mL PGE₂ but was decreased by 1400 pg/mL. Thus, mechanical stress controls bone formation by stimulating PGE₂ production and Ep2 and/or Ep4 expression in osteoblasts.

Keywords:

• Mechanical Stress
• Osteoblasts
• PGE₂
• PGE receptors
• Protein Kinase A