Proteoglycan degrading activity in granulomatous inflammation: comparison between the C57b1/6 and C57bg/bg mouse.
OBJECTIVE
Proteoglycan (GAG) and collagen are lost from cartilage juxtaposed to murine granulomatous tissue in both control and C57bg/bg (elastase deficient mice). The objective was to extract and characterise proteoglycan degrading activity within granulomas of both strains.


METHODS
15 animals (female C57b1/6 and C57bg/bg mice) per group were used.


METHODS
Cotton-wrapped rat femoral head cartilages were implanted subcutaneously into the dorsum of the mice and the granulomas excised fourteen days later.


METHODS
Granuloma and granuloma cell-granule preparations were fractionated within a detergent-based buffer and tested for their abilities to degrade cartilage in vitro in the presence and absence of enzyme inhibitors. Elastase and cathepsin G activities were also assessed using specific substrates. Statistical significance was calculated using Student's t-test.


RESULTS
Extracts from both strains induced the loss of cartilage GAG. This was correlated with cathepsin G activity (r = 0.96) and was inhibited by a specific cathepsin-G inhibitor (95%, p < 0.001), but not specific elastase or metalloproteinase inhibitors. Elastase activity but not that of cathepsin G was absent in the beige mice, whilst both enzymes were active in the controls.


CONCLUSIONS
It appears that neutrophil cathepsin G may play an important role in the degradation of cartilage proteoglycan in the murine cotton-pellet granuloma in both C57b1/6 and C57bg/bg.
Laboratoires Jacques LOGEAIS, Trappes, France.
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Willoughby
D000818:Animals; D002356:Cartilage / Q000378:metabolism; D056649:Cathepsin G; D002403:Cathepsins / Q000502:physiology*; D005260:Female; D006099:Granuloma / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010196:Pancreatic Elastase / Q000502:physiology; D011509:Proteoglycans / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012697:Serine Endopeptidases
D011509:Proteoglycans; D002403:Cathepsins; D012697:Serine Endopeptidases; D056649:Cathepsin G; C534096:Ctsg protein, mouse; C534097:Ctsg protein, rat; D010196:Pancreatic Elastase