H-1 and C-13 HR-MAS NMR investigations on native and enzymatically digested bovine nasal cartilage

Rheumatic diseases are accompanied by a progressive destruction of the cart ilage layer of the joints. Despite the frequency of the disease, degradatio n mechanisms are not yet understood and methods for early diagnosis are not available. Although some information on pathogenesis could be obtained fro m the analysis of degradation products of cartilage supernatants, the most direct information on degradation processes would come from the native cart ilage as such. We have used H-1 as well as C-13 HR-MAS (high resolution mag ic angle spinning) NMR spectroscopy to obtain suitable line-widths of NMR r esonances of native ge. 1D and 2D NMR spectra of native cartilage were comp ared with those of enzymatically-treated (collagenase and papain) samples. In the H-1 NMR spectra of native cartilage, resonances of polysaccharides, lipids and a few amino acids of collagen were detectable, whereas the C-13 NMR spectra primarily indicated the presence of chondroitin sulfate. Treatm ent with papain resulted only in small changes in the H-1 NMR spectrum, whe reas a clear diminution of all resonances was detectable in the C-13 NMR sp ectra. On the other hand, treatment with collagenase caused the formation o f peptides with an amino acid composition typical for collagen (glycine, pr oline, hydroxyproline and lysine). It is concluded that the HR-MAS NMR spec tra of cartilage may be of significance for the investigation of cartilage degradation since they allow the fast evaluation of cartilage composition a nd only very small amounts of sample are required. (C) 2001 Elsevier Scienc e B.V. All rights reserved.