ABSTRACT
Objective:To study the difference of the development between mandibular condylar cartilage and femoral head cartilage in vitro.Methods:Mandibular condyles and femoral heads were sampled from 1 2 neonatal mice and cultured in vitro.The samples before culture and after 6-week culture were examined by gross observation,HE staining,Alizarin Red staining and PCNA immunohistochem-istry respectively.Results:After in vitro culture,abnormal changes were observed in condyle cartilage,but the surface area of condyle cartilage was not changed(P >0.05).HE staining showed partial cartilage layer structure disappearance and the Alizarin Red staining confirmed calcification in the cartilage matrix.However,calcification was not found in femoral head cartilage,and the surface area of femoral head cartilage increased(P <0.05).HE staining showed the hypertrophied layer was thicker after culture than before and the Alizarin Red staining showed there was no calcification in the femoral cartilage matrix.The immunohistochemistry displayed PCNA posi-tive expression in both cartilage after culture.Conclusion:In vitro,the mandibular condylar cartilage matrix can be spontaneously cal-cificated.