Biomet Inc, 56 E Bell Drive, Warsaw, Indiana 46582, USA.
J Biomed Mater Res A. 2010 Dec 1;95(3):882-90. doi: 10.1002/jbm.a.32915.
In this study, we have investigated the effects of dissolved phosphorus and silicon on osteoblast differentiation in vitro. Neonatal rat calvarial osteoblasts were seeded on silica-calcium phosphate composites (SCPCS), hydroxyapatite (HA-200), and tissue culture polystyrene (TCPS) and incubated over 4 days in media containing 0 {minimal essential medium [MEM] (-)} or 3 mM β-glycerophosphate [MEM (+)]. Inductively coupled plasma analysis showed that P-content in original MEM (+) was 225% higher than that in MEM (-). Moreover, P-content in MEM (+) significantly increased to 3.4-4.4 mM and 3.6-4.7 mM after 2 and 4 days incubation with SCPC, respectively, owing to material dissolution and exogenous phosphate supplementation. In contrast, P-content in MEM (+) showed no change upon incubation with HA or TCPS. The P-content in MEM (-) incubated with SCPC was considerably lower than that in MEM (+). SCPC exhibited controlled Si-release in cell culture media [MEM (-) or MEM (+)], with Si-rich SCPC showing a significantly greater dissolution than Si-poor SCPC. Moreover, SCPC, unlike HA, demonstrated a cell- and solution-mediated dissolution over 4 days. Quantitative real-time PCR showed that in MEM (-), osteocalcin and osteopontin mRNA expression on Si-rich SCPC was significantly greater than that on HA, suggesting that Si plays an important role in enhancing bone-cell differentiation. However, osteoblast phenotypic expression on SCPC was significantly decreased after 4 days incubation in MEM (+), indicating that sustained exposure to elevated P-levels in the media can downregulate osteoblast function. Our results demonstrate that the controlled dissolution of SCPC provides a natural stimulus for bone-cell differentiation in vitro and could obviate the need of exogenous phosphate supplementation.
在这项研究中，我们研究了溶解磷和硅对体外成骨细胞分化的影响。将新生大鼠颅骨成骨细胞接种到硅钙磷复合材料（SCPCS）、羟基磷灰石（HA-200）和组织培养聚苯乙烯（TCPS）上，并在含有 0（最低必需培养基 [MEM]（-））或 3 mM β-甘油磷酸[MEM（+）]的培养基中孵育 4 天。电感耦合等离子体分析显示，原始 MEM（+）中的 P 含量比 MEM（-）高 225%。此外，由于材料溶解和外源性磷酸盐补充，MEM（+）中的 P 含量在与 SCPC 孵育 2 天和 4 天后分别显著增加到 3.4-4.4 mM 和 3.6-4.7 mM。相比之下，MEM（+）与 HA 或 TCPS 孵育时 P 含量没有变化。与 SCPC 孵育的 MEM（-）中的 P 含量明显低于 MEM（+）。SCPC 在细胞培养基[MEM（-）或 MEM（+）]中表现出可控的 Si 释放，富 Si 的 SCPC 比贫 Si 的 SCPC 具有更大的溶解度。此外，与 HA 不同，SCPC 在 4 天内表现出细胞和溶液介导的溶解。实时定量 PCR 显示，在 MEM（-）中，富 Si 的 SCPC 上的骨钙素和骨桥蛋白 mRNA 表达明显高于 HA，表明 Si 在增强骨细胞分化中起着重要作用。然而，SCPC 在 MEM（+）中孵育 4 天后，成骨细胞表型表达显著降低，表明培养基中持续暴露于升高的 P 水平会下调成骨细胞功能。我们的结果表明，SCPC 的受控溶解为体外骨细胞分化提供了自然刺激，并可能避免对外源性磷酸盐补充的需求。
