Hypo-osmotic stress induces calcium-dependent actin reorganization in articular chondrocytes

Osteoarthritis Cartilage. 2003 Mar;11(3):187-97. doi: 10.1053/s1063-4584(02)00347-3.


Objective: The aim of this study was to investigate the effects of hypo-osmotically induced calcium (Ca(2+)) transients on the organization of the actin cytoskeleton in articular chondrocytes. The secondary hypothesis tested was that actin restructuring following hypo-osmotic stress is mediated by gelsolin.

Methods: Isolated porcine chondrocytes were exposed to hypo-osmotic stress, and [Ca(2+)](i)was monitored using laser scanning microscopy. Calcium transients were monitored using fluorescent ratiometric imaging. The intracellular distribution of actin was examined using fluorescent immunohistochemistry and transient transfection with the pEGFP-actin plasmid. The intracellular distribution of gelsolin was investigated using fluorescent immunohistochemistry.

Results: Osmotic stress induced transient increases in [Ca(2+)](i)caused reorganization of intracellular actin through a mechanism that required Ca(2+)in the extracellular media. Fluorescence microscopy revealed that gelsolin was colocalized with F-actin immediately following hypo-osmotic stress but dissociated over time.

Conclusion: These results indicate that hypo-osmotic stress induces a gelsolin-mediated reorganization of actin through a transient increase in [Ca(2+)](i).

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism*
  • Animals
  • Calcium / pharmacokinetics*
  • Cartilage, Articular / metabolism*
  • Chondrocytes / metabolism*
  • Cytoskeleton / metabolism
  • Fluorescent Antibody Technique
  • Gelsolin / metabolism
  • Green Fluorescent Proteins
  • Indicators and Reagents
  • Inositol 1,4,5-Trisphosphate / analysis
  • Luminescent Proteins
  • Microscopy, Confocal
  • Osmosis / physiology
  • Swine


  • Actins
  • Gelsolin
  • Indicators and Reagents
  • Luminescent Proteins
  • Green Fluorescent Proteins
  • Inositol 1,4,5-Trisphosphate
  • Calcium