Site-specific effects of compression on macromolecular diffusion in articular cartilage.

In Vitro, Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't

Articular cartilage is the connective tissue that lines joints and provides a smooth surface for joint motion. Because cartilage is avascular, molecular transport occurs primarily via diffusion or convection, and cartilage matrix structure and composition may affect diffusive transport. Because of the inhomogeneous compressive properties of articular cartilage, we hypothesized that compression would decrease macromolecular diffusivity and increase diffusional anisotropy in a site-specific manner that depends on local tissue strain. We used two fluorescence photobleaching methods, scanning microphotolysis and fluorescence imaging of continuous point photobleaching, to measure diffusion coefficients and diffusional anisotropy of 70 kDa dextran in cartilage during compression, and measured local tissue strain using texture correlation. For every 10% increase in normal strain, the fractional change in diffusivity decreased by 0.16 in all zones, and diffusional anisotropy increased 1.1-fold in the surface zone and 1.04-fold in the middle zone, and did not change in the deep zone. These results indicate that inhomogeneity in matrix structure and composition may significantly affect local diffusive transport in cartilage, particularly in response to mechanical loading. Our findings suggest that high strains in the surface zone significantly decrease diffusivity and increase anisotropy, which may decrease transport between cartilage and synovial fluid during compression.

Full Text

Duke Authors

Cited Authors

  • Leddy, HA; Guilak, F

Published Date

  • November 15, 2008

Published In

Volume / Issue

  • 95 / 10

Start / End Page

  • 4890 - 4895

PubMed ID

  • 18689460

Electronic International Standard Serial Number (EISSN)

  • 1542-0086

Digital Object Identifier (DOI)

  • 10.1529/biophysj.108.137752

Language

  • eng

Citation Source

  • PubMed