OBJECTIVETo determine the effect of aspirin on cell proliferation, alkaline phosphatase (ALP) activity, cell cycle and apoptosis in murine bone marrow stromal cells, so as to explore an appropriate dose range to improve bone regeneration in periodontal treatment.

METHODSST2 cells were stimulated with aspirin (concentrations of 1, 10, 100 and 1 000 μmol/L) for 1, 2, 3, 5 and 7 d. Cell proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay. After ST2 cells were treated for 1, 3 and 7 d, ALP activity was measured by ALP kit, cell cycle and apoptosis were measured by flow cytometry (FCM) after treated for 48 h.

RESULTSMTT assays showed that various doses of aspirin have different effects on the cell growth. Briefly, lower concentrations (1, 10 μmol/L) of aspirin promoted the cell growth, the A value of 0, 1 and 10 μmol/L aspirin 7-day-treated cells were 0.313±0.012, 0.413±0.010 and 0.387±0.017 respectively (P <0.01 vs control), and so did the ALP level ([4.3±0.9], [6.0±0.3] and [7.7±0.4] μmol·min(-1)·g(-1), P <0.05 vs control), while higher concentrations, especially 1000 μmol/L of aspirin might inhibit the cell growth with time going, A value and ALP level were 0.267±0.016, (4.3±1.3) μmol·min(-1)·g(-1) respectively (P <0.05 vs control). Cell cycle analysis revealed no changes in comparison to control cells after treatment with 1 or 10 μmol/L aspirin, but it was observed that cell mitosis from S phase to G2/M phase proceeded at higher concentrations of 100 μmol/L aspirin, and the cell cycle in phase G0/G1 arrested at 1000 μmol/L. Parallel apoptosis/necrosis studies showed that the percentage of cells in apoptosis decreased dramatically at all doses of aspirin, the apoptosis rates of ST2 cells responded to 0, 1, 10, 100 and 1000 μmol/L aspirin were (11.50±0.90)%, (5.30±0.10)%, (5.50±0.10)%, (4.90±0.90)% and (7.95±0.25)% respectively (P<0.05 vs control).

CONCLUSIONSThis study demonstrated that lower dosage of aspirin can promote ST2 cells growth, osteogenic activity and inhibit its apoptosis. Aspirin maybe used for the bone reconstruction with a proper concentration.