DEGRADATION OF GLYCOSAMINOGLYCANS BY REACTIVE OXYGEN SPECIES DERIVED FROM STIMULATED POLYMORPHONUCLEAR LEUKOCYTES

The effect of reactive oxygen species (ROS), generated by in vitro sti mulation of isolated PMN upon the main GAG components of mineralised a nd non-mineralised connective tissues was investigated. PMN were isola ted from whole blood and the production of the ROS superoxide (O-2(.-) ) and hydroxyl radicals ((OH)-O-.) was stimulated by the addition of p horbol myristyl acetate (PMA) and PMA / FeCl3-EDTA chelate respectivel y and their production assessed over a 24 h period. The glycosaminogly cans (GAG), hyaluronan, chondroitin 4-sulphate and dermatan sulphate, were exposed to the ROS fluxes, incubated at 37 degrees C for 1 h and 24 h. GAG fragmentation was examined by gel exclusion chromatography a nd modification to hexuronic acid and hexosamine residues determined. Stimulation of PMN with PMA resulted in a burst of O-2(.-) production for 1 h, which was sustained at a reduced level for 24 h. Fragmentatio n of GAG was observed for all GAG examined. Modification to the GAG wa s evident, with hyaluronan being more susceptible to loss of GAG resid ues than sulphated GAG. Modification of sugar residues increased with the incubation time and loss of the hexuronic acid residues was greate r than loss of hexosamine residues. Addition of FeCl3-EDTA chelate, wh ich led to the generation of (OH)-O-. and was sustained over the 24 h period, demonstrated similar trends of GAG modification although incre ased degradation and loss of hexosamine and hexuronic acid were observ ed. GAG chains are constituents of PGs and their modification is likel y to affect the function of these macromolecules and be of importance in considering the pathogenesis of inflammatory diseases, including pe riodontal diseases. (C) 1997 Elsevier Science B.V.