Ripamonti U
South African Medical Research Council, Johannesburg.
J Bone Joint Surg Am. 1991 Jun;73(5):692-703.
The morphogenesis of bone in a porous hydroxyapatite substratum was studied after intramuscular implantation in adult primates. Replicas of porous hydroxyapatite that had been obtained after hydrothermal conversion of the calcium carbonate exoskeleton of coral (genus Goniopora) were implanted intramuscularly in twenty-four adult male baboons (Papio ursinus). Serial sections from specimens that had been harvested at three, six, and nine months showed that initially the formation of fibrous connective tissue was characterized by a prominent vascular component and by condensations of collagen fibers assembled at the interface of the hydroxyapatite. The morphogenesis of bone was intimately associated with the differentiation of the connective-tissue condensations. Bone formed without an intervening endochondral phase. Although the amount of bone varied considerably, in several specimens extensive bone developed, filling large portions of the porous spaces and culminating in total penetration by bone within the implants. The mean volume fraction composition of the specimens was 20.8 +/- 1.0 per cent (mean and standard error) for bone, 17.3 +/- 1.7 per cent for connective-tissue condensation, 31.9 +/- 1.0 per cent for fibrovascular tissue, 6.4 +/- 0.6 per cent for bone marrow, and 34.6 +/- 0.5 per cent for the hydroxyapatite framework. The amount of bone and marrow increased at each time-period, and the hydroxyapatite framework was significantly reduced between six and nine months. This indicated a moderate biodegradation over time, which was possibly a result of incomplete conversion of carbonate to hydroxyapatite. Linear regression analysis showed a negative correlation between the hydroxyapatite framework and the magnitude of bone formation within the porosities of the hydroxyapatite (p = 0.0001). Biochemical coating of the hydroxyapatite substratum with an allogeneic fibrin-fibronectin protein concentrate prepared from baboon plasma did not significantly increase the amount of bone formation within the porous spaces. The hydroxyapatite substratum may have functioned as a solid-phase domain for anchorage of bone morphogenetic proteins.
在成年灵长类动物肌肉内植入多孔羟基磷灰石基质后，对其骨形态发生进行了研究。将珊瑚（角孔珊瑚属）碳酸钙外骨骼经水热转化后得到的多孔羟基磷灰石复制品，肌肉内植入24只成年雄性狒狒（豚尾狒狒）体内。对在3个月、6个月和9个月时采集的标本进行连续切片，结果显示，最初纤维结缔组织的形成以显著的血管成分以及在羟基磷灰石界面处聚集的胶原纤维凝聚为特征。骨的形态发生与结缔组织凝聚的分化密切相关。骨的形成没有经过中间的软骨内阶段。尽管骨的量差异很大，但在几个标本中形成了大量的骨，填充了大部分孔隙，最终植入物内完全被骨穿透。标本的平均体积分数组成如下：骨为20.8±1.0%（平均值和标准误差），结缔组织凝聚为17.3±1.7%，纤维血管组织为31.9±1.0%，骨髓为6.4±0.6%，羟基磷灰石框架为34.6±0.5%。每个时间段骨和骨髓的量都增加，羟基磷灰石框架在6个月至9个月之间显著减少。这表明随着时间的推移有适度的生物降解，这可能是碳酸盐向羟基磷灰石不完全转化的结果。线性回归分析显示，羟基磷灰石框架与羟基磷灰石孔隙内骨形成的程度呈负相关（p = 0.0001）。用从狒狒血浆中制备的同种异体纤维蛋白 - 纤连蛋白蛋白浓缩物对羟基磷灰石基质进行生化包被，并没有显著增加孔隙内骨形成的量。羟基磷灰石基质可能起到了骨形态发生蛋白锚定的固相区域的作用。
