Cyclic mechanical strain regulates the PTHrP expression in cultured chondrocytes via activation of the Ca2+ channel

J Dent Res. 2005 Jan;84(1):64-8. doi: 10.1177/154405910508400111.

Abstract

The association between mechanical stimulation and chondrocyte homeostasis has been reported. However, the participation of PTHrP (parathyroid-hormone-related protein) in the mechano-regulation of chondrocyte metabolism remains unclear. We determined whether mechanical stimulation of chondrocytes induces the expression of PTHrP and, further, whether the mechano-modulation of PTHrP is dependent on the maturational status of chondrocytes. Cyclic mechanical strain was applied to rat growth plate chondrocytes at the proliferating, matrix-forming, and hypertrophic stages at 30 cycles/min. Cyclic mechanical strain significantly increased PTHrP mRNA levels in chondrocytes at the proliferating and matrix-forming stages only. The induction of PTHrP was dependent on loading magnitude at the proliferating stage. Using specific ion channel blockers, we determined that mechano-induction of PTHrP was inhibited by nifedipine, a Ca2+ channel blocker. These results suggest that mechanical induction of PTHrP possibly provides the environment for greater chondrocyte replication and matrix formation that would subsequently affect cartilage formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Calcium Signaling
  • Cell Differentiation
  • Cell Proliferation
  • Cells, Cultured
  • Chondrocytes / metabolism*
  • Extracellular Matrix Proteins / biosynthesis
  • Growth Plate / cytology
  • Male
  • Nifedipine / pharmacology
  • Parathyroid Hormone-Related Protein / biosynthesis*
  • Physical Stimulation
  • Polymerase Chain Reaction
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Wistar
  • Stress, Mechanical

Substances

  • Calcium Channel Blockers
  • Calcium Channels
  • Extracellular Matrix Proteins
  • Parathyroid Hormone-Related Protein
  • RNA, Messenger
  • Nifedipine