Abstract: Objective To investigate the ostegenesis by hydroxyapatite nanotube(HANT) in a calvarial defect model. Methods Bilateral full-thickness defects (5 mm in diameter) of parietal bone were created in twelve three -month-old SD rats. The left defected side was filled with 0.5 g HANT (patent number: Zl201010123277.5) as experimental side and the right side was set as control. CT were taken at 12 weeks postoperation. The rats were euthanized at 12 weeks after surgery and the specimens were harvested for patholologic analysis. Results There was no infection or death on the surgical models. CT examination demonstrated that the residual HANT powder could be seen on the experimental side of the skull defect, but the density is lower than bone. Pathologic analysis showed that bone defect in the control side was filled with fiber cells. The powder partly degraded in the experimental side, few chondrocytes were found, and a large number of fiber cells enwrapped the powder. Conclusion The HANT has good biocompatibility, but singly implanting the nanotube can't completely repair the skull defect of rats. Therefore, its osteogenic ability need to be refined in further experiment.

Key words: Hydroxyapatite nanotube, Rats, Calvarial defect