Objective To investigate the difference between anagenetic fibula with normal fibula in mechanical parameters, osteogenesis and tissue morphology,through establishing the model of fibula defect in rabbit.Methods Twenty New Zealand white rabbits were randomly divided.Model group were cuted the right fibula bone with 1.5 cm length.X-ray was used to observe the anagenetic fibula(half month,one month,two months).Stumped the anagenetic and normal fibula(1.5 cm)after two months. Three-point bending test was used to test the mechanical properties;alkaline phosphatase staining was checked the bone-formation ability;HE staining to check the tissue morphology.Results After half month a few new bone were formed at the edges of resec-tion area,one month later new bone were growed in the donor site,and after two month new fibula were completely formed.The three point bending test of fibula showed:there was no statistically significant difference between anagenetic fibula and normal fibu-la(P >0.05);alkaline phosphatase staining and HE staining showed the anagenetic fibula bone forming ability,histology had no sig-nificant difference compared with normal fibula.Conclusion Fibula were regenerated successfully after removing which retaining the periosteum.Compared with the normal fibula,there were no remarkable differences in mechanical parameters,osteogenesis and tissue morphology.

BACKGROUND:The mechanism of steroid-induced avascular necrosis of the femoral head is stil unclear, Cx43 protein as the main gap junction in bone tissue, through transmitting information between osteoblasts, regulates bone cel growth and differentiation, compensatory bone increase or decrease. The relationship between Cx43 protein and steroid-induced avascular necrosis of the femoral head is stil rarely reported.
OBJECTIVE:To explore the changes in Cx43 expression in rabbit models of steroid-induced vascular necrosis of the femoral head.
METHODS:Forty New Zealand rabbits were equal y and randomly divided into model group and control group. Rabbits in the model group were used to establish models of steroid-induced avascular necrosis of the femoral head using endotoxin and hormone. Rabbits in the control group were injected with the same volume of physiological saline at the same time points.
RESULTS AND CONCLUSION:At 4 weeks after model establishment, hematoxylin-eosin staining results revealed that in the model group, the trabecula became thin and distributed disorderly in the femoral subchondral area. Empty lacuna increased significantly. Adipocytes increased. Hematopoietic cel s in medul ary cavity apparently diminished. In the control group, trabecula arranged orderly and empty lacuna could be seen. Bone marrow cel s were abundant, but adipocytes were less. Immunohistochemical method demonstrated that Cx43 protein expression was observed in osteoblasts of the edge of trabecula, cytoplasm of osteoblasts of trabecula, and bone marrow stromal cel s. Western blot assay results showed that alkaline phosphatase and Cx43 protein expression was lower in the model group than in the control group (P<0.05). Results indicated that Cx43 protein expression decreased in the model rabbits, which may be the key link of the occurrence and development of steroid-induced avascular necrosis of the femoral head.