REACTION OF HYPOCHLOROUS ACID WITH BOVINE NASAL CARTILAGE COMPARISON TO PIG ARTICULAR-CARTILAGE

The action of sodium hypochlorite (NaOCl) on bovine nasal cartilage wa s studied by proton nuclear magnetic resonance (H-1-NMR) spectroscopy in order to model degradation processes of cartilage caused by neutrop hil-derived hypochlorous acid. Nasal cartilage was chosen as a mean of comparison because it differs from articular cartilage in its composi tion. It contains some more proteoglycans, i.e. polymeric carbohydrate s and less collagen than articular cartilage. This is important for st udying the influence of hypochlorous acid on cartilage components (col lagen and polysaccharides). Cartilage samples were incubated at 37 deg rees C with phosphate buffer in the presence or absence of NaOCl. Supe rnatants were collected and assayed by NMR-spectroscopy. In the presen ce of pure phosphate buffer, the supernatants of bovine nasal cartilag e were less rich in low molecular mass metabolites (e.g. amino acids, lactate) than articular cartilage. However, intense signals for highly mobile N acetyl groups of cartilage polysaccharides were detectable i n nasal cartilage. NaOCl caused an increase in signals for acetate and formiate. Signals for N-acetyl groups rose only during the first 25 m inutes of incubation with NaOCl. Then, their concentration decreased m arkedly. These changes were related to an enhanced release of chondroi tinsulfate from nasal cartilage.