Wnt/β-catenin, Indian hedgehog (Ihh)/Parathyroid-related peptide (PTHrP) and 
retinoid signaling pathways regulate cartilage differentiation, growth, and 
function during development and play a key role in endochondral ossification. 
The objective of this study was to elucidate the gene and protein expression of 
signaling molecules of these regulatory pathways in chondrocytes surrounding 
cartilage canals and the osteochondral junction during neonatal and 
pre-adolescent development. This study revealed cell-specific and age-related 
differences in gene and protein expression of signaling molecules of these 
regulatory pathways. A trend for higher gene expression of PTHrP along the 
cartilage canals and Ihh along the osteochondral junction suggests the presence 
of paracrine feedback in articular-epiphyseal cartilage. Differential expression 
of canonical (β-catenin, Wnt-4, Lrp4, Lrp6) and noncanonical Wnt signaling 
(Wnt-5b, Wnt-11) and their inhibitors (Dkk1, Axin1, sFRP3, sFRP5, Wif-1) 
surrounding the cartilage canals and osteochondral junction provides evidence of 
the complex interactions occurring during endochondral ossification.