BACKGROUND:In recent years, stem cel therapy for early osteonecrosis of the femoral head has become an alternative method, but the quality of stem cels is a key to the therapeutic outcomes. OBJECTIVE:To evaluate the proliferative ability and directional differentiation ability of autologous bone marrow mesenchymal stem cels in a rat model of steroid-induced femoral head necrosis. METHODS:Twenty Sprague-Dawley rats were randomly divided into control and observation groups with ten in each group. An animal model of steroid-induced femoral head necrosis was built in the observation group, and then bone marrow mesenchymal stem cels from rats in both two groups were isolated and cultured. Cel counting kit-8 was used to detect proliferation of passage 3 cels. Bone marrow mesenchymal stem cels at passage 3 were selected in the two groups for osteogenic and adipogenic induction. Alkaline phosphatase staining and alizarin red staining were adopted at 7 and 14 days of osteogenic induction, and oil red O staining as performed at 21 days of adipogenic induction. RESULTS AND CONCLUSION:The absorbance values of bone marrow mesenchymal stem cels were lower in the observation group than the control group at 1, 3, 5 days of culture, but there was no significant difference between two groups (P > 0.05). Until the 7th day of culture, the absorbance value and alkaline phosphatase activity in the observation group were significantly lower than that in the control group (P < 0.05). Additionaly, there were fewer calcium nodules and lipid droplets in the observation group compared with the control group. These findings suggest that the proliferative ability and directional differentiation ability of autologous bone marrow mesenchymal stem cels from a rat model of steroid-induced femoral head necrosis are both decreased.