Distribution and quantification of pyridinium cross-links of collagen within the different maturational zones of the chick growth plate.
In order to assess alterations in the collagen network during endochondral ossification the pyridinium cross-links of collagen were quantified in sequential transverse sections through the chick growth plate. This was accomplished using both morphological (alkaline phosphatase (ALP) histochemistry and collagen type X immunostaining) and analytical (HPLC) analyses. In articular cartilage, pyridinoline concentrations were maximal in the deep mature zones. In contrast, the proliferating chondrocyte zone of the growth plate had approximately a 10-fold greater pyridinoline cross-link concentration than the mature hypertrophic zone. Deoxypyridinoline was first found in the prehypertrophic zone of the growth plate cartilage that reacted positively for ALP activity but before collagen type X was detected. However, deoxypyridinoline concentrations were highest in the most differentiated regions of the growth plate where it was the principal pyridinium cross-link. In tibial dyschondroplasia, where chondrocyte differentiation is arrested in the prehypertrophic zone, higher concentrations of both cross-links were found with increasing distance down the lesion. We conclude that the decrease in pyridinoline cross-link concentration down the growth plate may be an essential adaptation (via increased collagenase activity and collagen turnover) of the matrix for vascular invasion and osteoclastic resorption to occur.
Farquharson
C
C
Roslin Institute [Edinburgh], Midlothian, UK. farquharson@bbsrc.ac.uk
Duncan
A
A
Seawright
E
E
Whitehead
C C
CC
Robins
S P
SP
D000818:Animals; D002645:Chickens; D003094:Collagen / Q000302:isolation & purification*; D003432:Cross-Linking Reagents; D006132:Growth Plate / Q000033:anatomy & histology / Q000737:chemistry*; D008297:Male; D010009:Osteochondrodysplasias / Q000473:pathology / Q000662:veterinary*; D011726:Pyridinium Compounds / Q000302:isolation & purification*; D014018:Tissue Distribution
D003432:Cross-Linking Reagents; D011726:Pyridinium Compounds; D003094:Collagen