Histochemical Studies of Chondrocyte Function in the Cartilage 41 



iour of the mandibular condyle and of the general biological processes with which its 

 cells are concerned. 



The cartilage can be divided into three distinct cell zones, namely the articular, 

 proliferative and hypertrophic zones. The articular zone provides an articular cover- 

 ing for the cartilage. The proliferative zone is concerned with growth and chondro- 

 genesis, and the hypertrophic zone shows the characteristics changes of cell hyper- 

 trophy and matrix production which precede ossification in cartilage. This latter zone 

 can be further divided into the premineralised and mineralised zones. 



Material and methods 



The mandibular condylar cartilages were removed from 48 male and female 

 Wistar rats of varying ages (19 days insemination age 1, 4, 8, 12, 14, 16 and 18 days 

 post-partum). Undemineralised cryostat sections of the cartilages were subjected 

 to a range of functional 



and analytical histochemical • ijjZ^'-^:.'' - '^ 



procedures including tech- *"ftBW'^> * •**-'-* 



niques for mitochondrial - ^ ' • ♦'-*' *> 



idative enzymes, lyso- *»^>,' ^ * V W^ ',' 



al and non-lysosomal f * iF- 



ox 

 som 



hydrolytic enzymes, proteins, ^■•%. , . * •'-"^^ 



carbohydrates and lipids. if •ilt4''l?;i'"', '■.'■% 



The position of the mine- 

 ralising front was deter- 

 mined microradiographically 

 and confirmed by the von 

 Kossa method. 



Observations 





mB' .^^.M 



Mitochondrial enzyme '•^t^^''^ %-"«^»' 





■¥■ 



activity was low in the 

 proliferative zone but in- 

 creased slightly in the ad- 

 jacent area of the hyper- 

 trophic zone and in the 

 articular zone. Activity in- 

 creased markedly with chon- 

 drocyte maturation and 

 reached maximum levels in 

 the hypertrophic zone se- 

 veral cells distant from the the presence 



mineralising front (Fig. 1) 

 Within the mineralising zone activity decreased. The correlation of the levels 

 of these enzymes with matrix production as evidenced by their increasing 

 activity in the cells of the hypertrophic zone and their decreased activity in the 

 mineralising zone supports the view that the primary function of these cells Is 

 probably matrix production. 



