Cartilage degradation by stimulated human neutrophils: elastase is mainly responsible for cartilage damage.
Although neutrophilic granulocytes are assumed to contribute to cartilage degradation during rheumatic diseases, there is still a discussion whether reactive oxygen species (ROS) or proteolytic enzymes that are both released by the neutrophils are most relevant to cartilage degradation. To gain further insight into these processes, an in vitro approach to study the interaction between the products of stimulated neutrophilic granulocytes and cartilage was used: Neutrophils from the blood of healthy volunteers were treated with different stimulators (e.g., Ca(2+) ionophores) in order to induce degranulation. Supernatants of neutrophils were afterward incubated with thin slices of pig articular cartilage. Some experiments were also performed in the presence of selected enzyme inhibitors. Supernatants of cartilage were subsequently assayed by one- and two-dimensional high-resolution proton NMR spectroscopy, and the content of soluble carbohydrates in the supernatant was additionally determined by biochemical methods. The selective inhibition of elastase decreased most significantly the extent of cartilage degradation, whereas all other inhibitors had much smaller effects. These results were additionally confirmed by measuring the effect of isolated elastase on articular cartilage in the absence and presence of different inhibitors. It is concluded that elastase released [EC 3.4.21.37] by neutrophils is the most relevant enzyme for cartilage degradation.
Hilbert
Nicole
N
Medical Faculty, Institute of Medical Physics and Biophysics, University of Leipzig, Liebigstrasse 27, 04103 Leipzig, Germany.
Schiller
Jürgen
J
Arnhold
Jürgen
J
Arnold
Klaus
K
D000818:Animals; D002241:Carbohydrates / Q000032:analysis; D002358:Cartilage, Articular / Q000378:metabolism*; D015550:Cell Degranulation; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006025:Glycosaminoglycans / Q000032:analysis / Q000378:metabolism; D006801:Humans; D018375:Neutrophil Activation / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013552:Swine
D002241:Carbohydrates; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D006025:Glycosaminoglycans; D010196:Pancreatic Elastase