A Comparison Of PTHrPmRNA Expression Between Mandibular Condyle Cartilage And Growth Plate Cartilage In The Early Development

[Objective] The purpose of this study is to investigate the differences in growth characteristics between condyle cartilage and growth plate during the early stage of development, discuss the effects of PTHrPmRNA in endochondral ossification, so that to further recognize the development process and growth characteristics of mandibular condyle cartilage.[Materials and Methods] Condyle cartilage and growth plate were gained from Sprague Dawley rat fetuses respectively on embryonic day 14 (E14), E15, E16, E17, E18 and E19. Made anteroposterior axes serial sections. Observe their structure in the way of HE staining, ISH was used to detect the expression of PTHrPmRNA. [Results] 1.During E14d—E19d, condyle cartilage and growth plate cartilage had similar structures. But there were some differences between them .One was their layers, the other was the shapes and cell alignment. Proliferative chondrocytes and prehypertrophic chondrocytes of growth plate cartilage were flatter than condyle cartilage. Chondrocytes of growth plate cartilage aligned with lone axis, became many cell columns. In contrast, chondrocytes of condyle cartilage arranged in layers. In growth plate, the time both of hypertrophic chondrocytes' presence and endochondral ossification taking place is earlier than in condyle cartilage. Furthermore, growth plate...