Effects of cell swelling on intracellular calcium and membrane currents in bovine articular chondrocytes

Clare E Yellowley-genetos, Jules C. Hancox, Henry J. Donahue

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Chondrocytes experience a dynamic extracellular osmotic environment during normal joint loading when fluid is forced from the matrix, increasing the local proteoglycan concentration and therefore the ionic strength and osmolarity. To exist in such a challenging environment, chondrocytes must possess mechanisms by which cell volume can be regulated. In this study, we investigated the ability of bovine articular chondrocytes (BAC) to regulate cell volume during a hypo-osmotic challenge. We also examined the effect of hypo-osmotic stress on early signaling events including [Ca2+]i and membrane currents. Changes in cell volume were measured by monitoring the fluorescence of calcein-loaded cells. [Ca2+]i was quantified using fura-2, and membrane currents were recorded using patch clamp. BAC exhibited regulated volume decrease (RVD) when exposed to hypo-osmotic saline which was inhibited by Gd3+. Swelling stimulated [Ca2+]i transients in BAC which were dependent on swelling magnitude. Gd3+, zero [Ca2+]o, and thapsigargin all attenuated the [Ca2+]i response, suggesting roles for Ca2+ influx through stretch activated channels, and Ca2+ release from intracellular stores. Inward and outward membrane currents significantly increased during cell swelling and were inhibited by Gd3+. These results indicate that RVD in BAC may involve [Ca2+]i and ion channel activation, both of which play pivotal roles in RVD in other cell types. These signaling pathways are also similar to those activated in chondrocytes subjected to other biophysical signals. It is possible, then, that these signaling events may also be involved in a mechanism by which mechanical loads are transduced into appropriate cellular responses by chondrocytes.

Original languageEnglish (US)
Pages (from-to)290-301
Number of pages12
JournalJournal of Cellular Biochemistry
Volume86
Issue number2
DOIs
StatePublished - 2002
Externally publishedYes

Fingerprint

Intracellular Membranes
Chondrocytes
Swelling
Joints
Calcium
Membranes
Thapsigargin
Fura-2
Cell Size
Clamping devices
Proteoglycans
Ionic strength
Ion Channels
Fluorescence
Chemical activation
Osmolar Concentration
Fluids
Monitoring
Osmotic Pressure

Keywords

  • Gadolinium
  • Ion channel
  • Mechanotransduction
  • Osmolarity
  • Regulatory volume decrease

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology

Cite this

Effects of cell swelling on intracellular calcium and membrane currents in bovine articular chondrocytes. / Yellowley-genetos, Clare E; Hancox, Jules C.; Donahue, Henry J.

In: Journal of Cellular Biochemistry, Vol. 86, No. 2, 2002, p. 290-301.

Research output: Contribution to journalArticle

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