Growth factors in the initial stage of bone formation, analysis of their expression in chondrocytes from epiphyseal cartilage of rat costochondral junction

In endochondral ossification septoclasts and osteoclasts (also called chondroclasts) release growth factors deposited in non-calcified and calcified zones of the growth plate. They stimulate, within the metaphysis, initial stages of the bone formation. We have recently reported quantitation of several growth factors in calcified cartilage from calf costochondral junction. Data from the analogous human cartilage could possibly help to choose efficient combinations of growth factors for clinical applications, but the amount of the calcified cartilage needed for analysis of numerous growth factors would be difficult to collect. The estimation of growth factors expression in endochondral chondrocytes may, indirectly, indicate which of them play a leading role in the stimulation of osteoprogenitor cells in metaphysis. To test this hypothesis, we used rat chondrocytes to evaluate mRNA levels of several growth factors.