NMR-STUDIES OF THE ACTION OF HYPOCHLOROUS ACID ON NATIVE PIG ARTICULAR-CARTILAGE

The action of sodium hypochlorite on pig articular cartilage was studi ed by H-1-NMR spectroscopy to model some aspects of degradation proces ses of cartilage during rheumatoid arthritis. Two effects of NaOCl on cartilage polysaccharides have been observed. Hypochlorous acid causes an enhanced release of oligomeric polysaccharides from cartilage. The second effect concerns the degradation of N-acetyl side chains of car bohydrates to acetate via a chlorinated transient product. Signal inte nsities for N-acetyl groups (approximate to 2.0 ppm) increase during t he first 2 h of incubation of cartilage with NaOCl. Then they decrease again. However, acetate (1.90 ppm) as the final product of degradatio n of N-acetyl side chains increases continuously over the period of in cubation with NaOCl. In addition to polysaccharides, effects of NaOCl were only observed in cartilage samples on amino acids like alanine. T he alanine resonance disappeared already at NaOCl concentrations where only small effects on cartilage polysaccharides have been observed.