ABSTRACT
To investigate the changes of expression location and amount of CUL7 and CCDC8 proteins in the growth plate of normal mice aged 0-4 weeks, and to clarify the roles of CUL7 and CCDC8 proteins in the proliferation and differentiation of tibia growth plate of mice. The expression location and levels of CUL7 and CCDC8 proteins in the tibial growth plate of normal mice aged 0-4 weeks were observed with immunohistochemical staining. CUL7 protein was expressed in the cell cytoplasm and membrane in three zones of tibial growth plate three bands at 0-4 weeks. The expression level and total expression level of CUL7 protein in each zone of growth plate decreased gradually with the increase of week of age( F=369.61, P=0.001). The expression of CUL7 protein decreased most significantly in the proliferative zone, followed by the stationary zone and the hypertrophic zone. CCDC8 protein was mainly expressed in proliferation zone and hypertrophic zone cell membrane and nuclear membrane of growth plate at 0-2 weeks, and mainly expressed in hypertrophic zone cell membrane and nuclear membrane at 3-4 weeks. The expression of CCDC8 protein in the proliferating zone changed inversely with week of age, and the expression of CCDC8 protein in the hypertrophic zone increased over 4 weeks( F=453.67, P<0.001). The total expression of CCDC8 protein in growth plates decreased with the increase of week of age.The expression levels of CUL7 and CCDC8 decreased with the increase of week of age, suggesting that CUL7 and CCDC8 may promote the proliferation and differentiation of growth plate chondrocytes.