HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Price, F M Articles by Mason, R M Search for Related Content PubMed PubMed Citation Articles by Price, F M Articles by Mason, R M

Department of Physiology, St George's Hospital Medical School, London, UK.

1. The hydraulic resistance of the synovial lining of a joint, a key coupling coefficient in synovial fluid turnover, is thought to depend on the concentration of biopolymers (glycosaminoglycans (GAGs) and collagen) in the synovial intercellular spaces, because these polymers create hydraulic drag. The primary aim of this study was to obtain microscopically separated, milligram samples of the very thin synovium from eight rabbit knees, and to analyse these quantitatively for GAGs (chondroitin sulphate, heparan sulphate and hyaluronan) and collagen to allow comparison with published hydraulic resistance data. Synovial fluid and femoral cartilage were also studied. 2. Synovium comprised 73 +/- 3% water by weight (mean +/- S.E.M.). Of the 270 mg solid per gram of wet tissue, protein formed 136 mg (by automated amino acid analysis), and of this 94 mg was collagen by hydroxyproline analysis. From the collagen mass and fibril volume fraction (0.153 of tissue by morphometry), fibrillar specific volume was calculated to be 1.43 ml per gram of molecular collagen, and fibril water content 47% by volume. 3. The concentration of chondroitin 4-sulphate (C4S) plus chondroitin 6-sulphate (C6S), measured by capillary zone electrophoresis was 0.55 mg per gram of synovium--much greater than in synovial fluid (0.04 mg g-1) and much less than in cartilage (27.8 mg g-1). The C4S/C6S ratio in synovium (7.3) differed from that in cartilage (0.7), indicating that different proteoglycans predominated in synovium. The heparan sulphate concentration, assayed by radioactive Ruthenium Red binding, was 0.92 mg per gram of synovium (synovial fluid, 0.08 mg g-1; cartilage, 0.72 mg g-1). 4. In contrast to sulphated GAGs, the hyaluronan concentration was highest in synovial fluid (3.53 mg g-1; biotinylated G1 domain binding assay). The concentration in synovial interstitium was only 0.56 mg g-1 (corrected for interstitial volume fraction, 0.66), even though there is open contact between synovial interstitium and synovial fluid. This may be due to exclusion or washout. 5. Total GAG mass was approximately 4 mg per gram of synovial interstitium. A model of trans-synovial flow indicated that a uniform GAG concentration of 4 mg g-1 is less than 1/3rd of that required to explain the experimental estimate of synovial hydraulic resistance. Errors in the resistance estimate do not appear to be large enough to resolve the problem. It is possible, therefore, that additional polymeric material in the interstitium, such as glycoproteins and proteoglycan core protein, may contribute to the hydraulic resistance.

This article has been cited by other articles:

				S. Sabaratnam, R. M. Mason, and J. R. Levick Filtration rate dependence of hyaluronan reflection by joint-to-lymph barrier: evidence for concentration polarisation J. Physiol., June 15, 2004; 557(3): 909 - 922. [Abstract] [Full Text] [PDF]