Document Detail

Association of collagenase and tissue inhibitor of metalloproteinases (TIMP) with hypertrophic cell enlargement in the growth plate.
MedLine Citation:
PMID:  2559303     Owner:  NLM     Status:  MEDLINE    
In the transition from proliferating to hypertrophic cell zones in the growth plate, there is an increased in chondrocyte cell volume and a corresponding decrease in collagen content to allow for cell enlargement. To substantiate our hypothesis that collagenase is responsible for these changes, growth plates from rats treated with bisphosphonate (HEBP) were compared histologically and biochemically with growth plates from normal and vitamin D and phosphate deficient (-VDP) rats. HEBP-treated rats developed an expanded hypertrophic cell zone (HCZ) characterized by the presence of two distinct populations of hypertrophic cells. The proximal hypertrophic cells were only 2-fold enlarged compared to the proliferating cells, whereas 1/6 of the distal hypertrophic cells were enlarged almost 5-fold and appeared morphologically identical with hypertrophic cells from normal and -VDP rats. The HEBP growth plates were divided into cross-sectional thirds and analyzed for active and latent collagenase. The juxta-metaphyseal (lower 1/3) cartilage contained 100% of the fully enlarged hypertrophic cells and appeared identical to those found in normal and -VDP growth plates, along with 81% of the active and 77% of the total collagenase. Collagenase and tissue inhibitor of metalloproteinases (TIMP) were measured in extracts of similarly divided tissues. The presence of true collagenas was confirmed by using [3H]-telopeptide-free collagen. TIMP levels were inversely related to the presence of active collagenase and cellular hypertrophy. Substantial levels of latent collagenase were found in the extracellular fluid at sites of active collagenolysis, but not in the fluid phase surrounding the 2-fold enlarged hypertrophic cells. It is postulated that increased amounts of active collagenase and insufficient levels of TIMP may account for the reduced collagen content seen in the lower HCZ of both -VDP and HEBP rickets. Unlike active collagenase, which remains localized by binding to collagen, latent enzyme is probably restricted in its mobility throughout the extracellular space by diffusion, itself, or the interstices of the extracellular matrix.
D D Dean; O E Muniz; D S Howell
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Matrix (Stuttgart, Germany)     Volume:  9     ISSN:  0934-8832     ISO Abbreviation:  Matrix     Publication Date:  1989 Nov 
Date Detail:
Created Date:  1990-03-14     Completed Date:  1990-03-14     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8906139     Medline TA:  Matrix     Country:  GERMANY, WEST    
Other Details:
Languages:  eng     Pagination:  366-75     Citation Subset:  IM    
Arthritis Research Laboratory, U.S. Veterans Administration Medical Center, Miami, FL.
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MeSH Terms
Collagen / metabolism
Glycoproteins / metabolism*
Growth Plate / metabolism,  pathology*
Hypertrophy / complications,  pathology
Microbial Collagenase / antagonists & inhibitors*,  metabolism
Rats, Inbred Strains
Rickets / complications,  pathology
Tissue Inhibitor of Metalloproteinases
Grant Support
Reg. No./Substance:
0/Glycoproteins; 0/Tissue Inhibitor of Metalloproteinases; 9007-34-5/Collagen; EC Collagenase

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