Alper G, Bernick S, Yazdi M, Nimni M E
Department of Medicine, University of Southern California School of Medicine, Los Angeles.
Am J Med Sci. 1989 Dec;298(6):371-6. doi: 10.1097/00000441-198912000-00003.
Hydroxyapatite (HA) and Demineralized Bone Matrix (DBM) are being investigated as potential osteogenic agents with hopes that these substances can be used to induce bone formation in non-union fractures. This study was done to determine the relative effects of HA and DBM implanted as moldable phospholipid composites in bone defects that result in non-unions. We studied 22 ten-month-old Long-Evans male rats with 5.0 mm unilateral radial defects implanted with HA, DBM, and a combination of both substances. Control defects were left unfilled. Eight weeks after implantation, the histological sections demonstrated a decrease in bone formation with HA relative to controls. The HA crystals were encapsulated by connective tissue stroma made up of collagenous elements, fibroblasts, and blood vessels. There were no indications of bone formation within the fibrous stroma. 45Calcium, alkaline phosphatase, and bone gla protein (BGP) assays demonstrated a 16% increase in bone formation in rats implanted with DBM, an 80% decrease in groups implanted with HA (p = 0.01) and an 80% decrease with DBM plus HA (p = 0.01). Radiologic analysis corresponds well with histological and biochemical results. We conclude that osteogenesis in non-union defects is enhanced by the implantation of DBM, while HA interferes with bone formation in the rat model. In the presence of both substances, HA appears to impede new bone growth, negating any positive effects seen with DBM.
羟基磷灰石（HA）和脱矿骨基质（DBM）作为潜在的成骨剂正在接受研究，人们希望这些物质可用于诱导骨不连骨折处的骨形成。本研究旨在确定作为可塑形磷脂复合物植入的HA和DBM在导致骨不连的骨缺损中的相对作用。我们研究了22只10个月大的Long-Evans雄性大鼠，其单侧桡骨有5.0 mm的缺损，并植入了HA、DBM以及这两种物质的组合。对照缺损未进行填充。植入8周后，组织学切片显示，相对于对照组，HA组的骨形成减少。HA晶体被由胶原成分、成纤维细胞和血管组成的结缔组织基质包裹。在纤维基质内未发现骨形成的迹象。45钙、碱性磷酸酶和骨钙素（BGP）检测表明,植入DBM的大鼠骨形成增加了16%，植入HA的组减少了80%（p = 0.01），而植入DBM加HA的组减少了80%（p = 0.01）。放射学分析与组织学和生化结果非常吻合。我们得出结论，在大鼠模型中，植入DBM可增强骨不连缺损处的骨生成，而HA会干扰骨形成。在两种物质同时存在的情况下，HA似乎会阻碍新骨生长，抵消DBM所产生的任何积极作用。
