R. Moseley et al., THE MODIFICATION OF ALVEOLAR BONE PROTEOGLYCANS BY REACTIVE OXYGEN SPECIES IN-VITRO, Connective tissue research, 37(1-2), 1998, pp. 13-28
Reactive oxygen species (ROS) are being increasingly implicated in the
connective tissue degradation associated with chronic inflammatory co
nditions, such as periodontal disease. The present study investigated
the effects of ROS on the proteoglyans (PG) of alveolar bone which are
important structural components within the periodontium. PG were isol
ated from ovine alveolar bone and exposed to increasing concentrations
of hydrogen peroxide (H2O2) or to a hydroxyl radical ((OH)-O-.) flux
for 1h or 24h, and the degradation products examined for depolymerisat
ion and chemical modification of the PG structure, ROS were demonstrat
ed to be capable of degrading alveolar bone PG in vitro, the (OH)-O-.
species resulting in greater modification than H2O2, The degradative e
ffects observed included cleavage of the protein core and depolymerisa
tion of the GAG chains. The core proteins were more susceptible to deg
radation than the GAG chains in the presence of H2O2 alone, although b
oth the core proteins and the GAG chains were extensively degraded in
the presence of a (OH)-O-. flux for bath 1h and 24h, Exposure of the P
G to (OH)-O-. for 24h resulted in significant modification to the amin
o acid composition with decreases in the proportion of leucine and the
complete loss of proline, tyrosine and phenylalanine evident. The res
ults highlight the potential role of ROS as an important mechanism in
considering the pathology of periodontal tissue destruction.