RESUMO
BACKGROUND:Activating transcription factor 4 is found as an activating factor that can regulate osteogenic differentiation and function, and plays a critical role in the osteogenic differentiation. OBJECTIVE:To investigate the expression and significance of activating transcription factor 4 in the osteogenic differentiation of bone marrow mesenchymal stem cells from Sprague-Dawley rats. METHODS:Bone marrow mesenchymal stem cells from Sprague-Dawley rats were cultured using the whole bone marrow adherence method, and ossification revulsant was added to induce passage 3 cells. cells with no osteogenic induction served as controls. RT-PCR and western blot assay were employed to dynamical y monitor expression of activating transcription factor 4. RESULTS AND CONCLUSION:RT-PCR results showed that activating transcription factor 4 mRNA expression increased with the increasing osteogenic differentiation, and peaked at day 16. Western blot analysis showed that the protein expression of activating transcription factor 4 tended to increase with the increasing osteogenic differentiation, peaked at day 16 and stil maintained at a higher level at day 19. Compared with the uninduced cells, activating transcription factor 4 in the induced cells exhibited a higher expression at mRNA and protein levels (P<0.05). These findings indicate that activating transcription factor 4 expression is elevated during osteogenic differentiation, showing a positive correlation with osteogenic ability of bone marrow mesenchymal stem cells.