Calcium hydroxide regulates bone sialoprotein gene transcription in human dental pulp cells / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To analyze the effects of calcium hydroxide [Ca(OH)2] on transcription of the bone sialoprotein (BSP) gene in human dental pulp cells.</p><p><b>METHODS</b>Human dental pulp tissues were collected from extracted teeth for orthodontic reason. In cell culture media, different dose (0.012, 0.120, 0.400 and 1.200 mmol/L) of Ca(OH)2 was added. Total RNA of cells were extracted. The best dose of Ca(OH)2 on human BSP was determined with the real-time polymerase chain reaction (PCR). Further, the time (0, 3, 6, 12, 24 h) effects of the best dose Ca(OH)2 on human BSP, runt-related transcription factor-2 (Runx-2) and osterix (OSX) mRNA levels were determined with PCR. Further method included transient transfection assays, linking chimeric constructs of the human BSP gene promoter to a luciferase reporter gene, then ransfected using lipofectamine in cells and measured the luciferase activities of BSP gene promoter.</p><p><b>RESULTS</b>With the real-time PCR, the optimal Ca(OH)2 concentration was determined as 1.200 mmol/L. With this concentration at different time points (0, 3, 6, 12 and 24 h), the levels of BSP mRNA increased at 6 h (1.45 ± 0.36), reached maximal at 12 h (2.66 ± 0.18); the levels of Runx-2mRNA increased at 6 h (2.38 ± 0.08), at 12 h (2.73 ± 0.16), and decreased at 24 h. OSX mRNA could be recognized at 12 h, reached maximal levels at 24 h (3.30 ± 0.062). Transient transfection assays showed that treatment of human dental pulp cells with Ca(OH)2 (1.200 mmol/L) increased the luciferase activities of the constructs between -84LUC and -868LUC at 12 h (2.00 ~ 2.60 fold).</p><p><b>CONCLUSIONS</b>This study demonstrate that Ca(OH)2 could stimulate BSP transcription between -84LUC and -868LUC in the human BSP gene promoter in human dental pulp cells.</p>