BACKGROUND: Previous research has investigated the effect of nano-zirconium dioxide-toughened hydroxyapatite (nano-ZrO2-HA) on the proliferation and differentiation of rabbit bone marrow stromal cells.OBJECTIVE: To evaluate the biocompatibility of nano-ZrO_2-HA compound.METHODS: The experiments of acute toxicity,subacute toxicity,pyrogen,hemolysis,and intramuscular implantation were performed on New Zealand rabbits,healthy adult Kunming mice,and adult rats according to "Technical Evaluation Standards of Biomedical Materials and Medical Instruments",promulgated by Chinese Board of Health.RESULTS AND CONCLUSION: Acute toxicity: All experimental animals survived.There was no significant difference in body mass before and after testing (P> 0.05).Pyrogen: Heating reaction was not tested.Hemolysis: Generally speaking,hemolytic crisis was not observed after 1 hour,and hemolytic rate was less than 5%.Intramuscular implantation: Infection did not occur in any animals,and materials were not discharged at all.Four weeks later,muscles were closely integrated with materials.A certain quantity of tissue grew into material pore,and peripheral muscle still had normal morphology and structure.Subacute toxicity:There was no significant difference in body mass and blood routine before and 2 weeks after testing.HE staining demonstrated that necrotic focus and other lesion were not observed in heart,liver,and kidney tissues under optic microscope.The results suggested that nano-ZrO_2-HA was non-toxicity,and it had no pyrogen and hemolysis effect,as well as it did not stimulate to the muscle of rabbit.Inflammatory rejection did not happen to the animal.The nano-ZrO_2-HA was closely integrated with the muscle,characterizing by great biocompatibility.Therefore,it can be used as substitution materials in clinical experiment.But it still needs to be evaluated completely.