Cartilage degradation by stimulated human neutrophils: reactive oxygen species decrease markedly the activity of proteolytic enzymes.
BACKGROUND
Although neutrophilic granulocytes clearly contribute to cartilage degradation in rheumatic diseases, it is unclear if reactive oxygen species (ROS) or proteolytic enzymes are the most important components in cartilage degradation and how they interact.


RESULTS
Neutrophils were stimulated by chemicals conferring a different degree of ROS formation and enzyme release. Supernatants of neutrophils were incubated with thin slices of pig articular cartilage. Supernatants of cartilage were assayed by NMR spectroscopy, MALDI-TOF mass spectrometry and relevant biochemical methods. Stimulation conditions of neutrophils correlated well with the extent of cartilage degradation. Due to the release of different enzymes, cartilage degradation could be best monitored by NMR since mainly low-mass degradation products were formed. Astonishingly, the suppression of the formation of ROS resulted in decreased cartilage degradation.


CONCLUSIONS
ROS formed by neutrophils are not directly involved in cartilage degradation but influence the activity of proteolytic enzymes, which are the main effectors of cartilage degradation.
Schiller
J
J
Institute of Medical Physics and Biophysics, Medical Department, University of Leipzig, Germany. schij@server3.medizin.uni-leipzig.de
Benard
S
S
Reichl
S
S
Arnhold
J
J
Arnold
K
K
D000818:Animals; D001172:Arthritis, Rheumatoid / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D001713:Biphenyl Compounds / Q000494:pharmacology; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D011509:Proteoglycans / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013552:Swine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001713:Biphenyl Compounds; D017077:Culture Media, Conditioned; D009861:Onium Compounds; D011509:Proteoglycans; D017382:Reactive Oxygen Species; C031291:diphenyliodonium; D003571:Cytochalasin B; D009240:N-Formylmethionine Leucyl-Phenylalanine; D010450:Endopeptidases; D013755:Tetradecanoylphorbol Acetate