Fatty acid transport in articular cartilage.
Articular cartilage extracellular matrix imposes a significant transport barrier to albumin, the principal carrier of fatty acids. It has not been previously established whether it also influences the transport of fatty acids important for chondrocyte metabolism. Albumin was labelled with rhodamine-maleimide and bound to NBD-labelled lauric acid. Plugs of fresh equine metacarpal-phalangeal cartilage and subchondral bone were incubated with the complex at 4 degrees C for 2-160 h. The fluorophore distribution was quantified using quantitative microscopy in histological sections. The fluorescence intensity of both fluorophores fell steeply over 300 microm below the articular surface and remained relatively uniform through the mid zone but the ratio of lauric acid to albumin was higher than in the incubation medium. The effective diffusivity of lauric acid in the mid zone was (2.2+/-0.7) x 10(-12) m2 s(-1) (n = 33), higher than that of the carrier albumin, suggesting dissociation in the surface layer. Lauric acid accumulated reversibly at the tidemark.
Arkill
Kenton Paul
KP
Biomedical Physics Group, School of Physics, University of Exeter, Exeter, EX4 4QL, UK. k.p.arkill@ex.ac.uk
Winlove
C Peter
CP
D000818:Animals; D001693:Biological Transport, Active / Q000502:physiology; D002358:Cartilage, Articular / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D006736:Horses; D066298:In Vitro Techniques; D012709:Serum Albumin / Q000378:metabolism*
D005227:Fatty Acids; D012709:Serum Albumin