[Effect of human tooth bone graft materials on proliferation and differentiation of mice mononuclear macrophage RAW264.7].

OBJECTIVE

To investigate the effect of human tooth bone graft materials on the proliferation, differentiation, and morphology of macrophages, and to understand the biocompatibility and cytotoxicity of human tooth bone graft materials.

METHODS

Fresh human teeth were collected to prepare human tooth bone graft materials, the adhesion of mouse mononuclear macrophages RAW264.7 to human bone graft materials was observed under confocal microscopy. Scanning electron microscopy was used to observe the morphology of human tooth bone graft materials, OSTEONⅡ synthetic highly resorbable bone grafting materials, and untreated tooth powder (dental particles without preparation reagents). Different components of the extract were prepared in 4 groups: group A (DMEM medium containing 10% fetal bovine serum), group B (human tooth bone graft materials), group C (OSTEONⅡ synthetic highly resorbable bone grafting materials), group D (untreated tooth powder without preparation reagents). The 4 groups of extracts were co-cultured with the cells, and the cytotoxicity was qualitatively determined by observing the cell morphological changes by inverted microscope. The cell proliferation and differentiation results and cell relative proliferation rate were determined by MTT method to quantitatively determine cytotoxicity. The cell viability was detected by trypanosoma blue staining, and tumor necrosis factor α (TNF-α ) and interleukin 6 (IL-6) expressions were detected by ELISA.

RESULTS

Scanning electron microscopy showed that the surface of the human tooth bone graft material and the OSTEONⅡ synthetic highly resorbable bone grafting materials had a uniform pore structure, while the untreated tooth particle collagen fiber structure and the demineralized dentin layer collapsed without specific structure. Confocal microscopy showed that the cells grew well on human tooth bone graft materials. After co-culture with the extract, the morphology and quantity of cells in groups A, B, and C were normal, and the toxic reaction grades were all grade 0, while group D was grade 3 reaction. MTT test showed that the cytotoxicity of groups B and C was grade 0 or 1 at each time point, indicating that the materials were qualified. The cytotoxicity was grade 2 in group D at 1 day after culture, and was grade 4 at 3, 5, and 7 days. Combined with cell morphology analysis, the materials were unqualified. The trypanosoma blue staining showed that the number of cells in groups A, B, and C was significantly higher than that in group D at each time point ( <0.05), but no significant difference was found among groups A, B, and C ( <0.05). ELISA test showed that the levels of TNF-α and IL-6 in groups A, B, and C were significantly lower than those in group D ( <0.05), but no significant difference was found among groups A, B, and C ( <0.05).

CONCLUSION

The human tooth bone graft materials is co-cultured with mice mononuclear macrophages without cytotoxicity. The extract has no significant effect on cell proliferation and differentiation, does not increase the expression of inflammatory factors, has good biocompatibility, and is expected to be used for clinical bone defect repair.