Chang Shih-Hsin, Hsu Yuan-Ming, Wang Yng Jiin, Tsao Yeou-Ping, Tung Kwan-Yi, Wang Tao-Yuan
Plastic Surgery, Mackay Memorial Hospital, Taipei, Taiwan.
J Mater Sci Mater Med. 2009 Jan;20(1):23-31. doi: 10.1007/s10856-008-3507-1. Epub 2008 Jul 24.
Reconstruction of large segment of bony defects is frequently needed in hand surgery. Autogenous bone grafting is considered the standard in management of these bony defects but has limited source of graft material. Collagen and hydroxyapatite have been used as bone-filling materials and are known to serve as the osteoconductive scaffold for bone regeneration. On the other hand, platelet-rich plasma is a kind of natural source of growth factors, and has been used successfully in bone regeneration and improving wound healing. This study was designed to evaluate the effectiveness of using biohybrids of platelet-rich plasma and collagen-hydroxyapatite beads for fabricating of protrusive bone in a rabbit animal model.
Biomaterial beads comprised of particulate hydroxyapatite dispersed in fibrous collagen (type I) matrices were prepared and filled in the ringed polytetrafluoroethylene (PTFE) artificial vascular graft (3 cm long, 1 cm in diameter). New Zealand White rabbits were each implanted with two cylindrical PTFE artificial vascular graft over both iliac crests (n = 16). A 2 x 0.5 cm opening was created at the side of each PTFE chamber to allow the content of chamber in contact with the bone marrow of the ileum. The chambers were empty (groups A and D), filled with type I collagen/hydroxyapatite beads (groups B and C). In groups C and D, autologous platelet rich plasma (PRP) was given by transcutaneous injection method into the chambers every week. After 12 weeks, the animals were sacrificed and the chambers were harvested for radiological and histological analysis.
In plain radiographs, the group C chambers had significantly higher bone tissue engineered (average calcified density 0.95, average calcified area 61.83%) compared with other groups (P < 0.001). In histological examination, there was a creeping substitution of the implant by the in-growth of fibrovascular tissue in group C. Abundant fibrovascular networks positioned interstitially between these biomaterial beads in all parts of chamber. Degradation of these beads and newly formed capillaries and osteoids around the degraded matrixes are shown. The continually calcification in the matrixes or degraded matrixes is evidenced by the strong green fluorescence observed under the confocal microscope. In group B, looser architecture without evidence of tissue in-growth was shown. In the scaffold absent groups (A and D), there was only fibrous tissue shown within the chamber.
In this study, we have demonstrated a feasible approach to fabricate an osseous tissue that meets clinical need. Using the type I collagen/ hydroxyapatite gel beads matrixes and intermittent injection of autologous platelet-rich-plasma, specific 3D osseous tissues with fibrovascular network structure from pre-exist bony margin were successfully created in an in vivo animal model.
手部手术中常常需要对大段骨缺损进行修复。自体骨移植被视为治疗这些骨缺损的标准方法，但移植材料来源有限。胶原蛋白和羟基磷灰石已被用作骨填充材料，并且已知它们可作为骨再生的骨传导支架。另一方面，富血小板血浆是一种天然的生长因子来源，并已成功用于骨再生和促进伤口愈合。本研究旨在评估在兔动物模型中使用富血小板血浆与胶原 - 羟基磷灰石珠的生物复合材料制造突出骨的有效性。
制备由分散在纤维状I型胶原蛋白基质中的颗粒状羟基磷灰石组成的生物材料珠，并填充到带环的聚四氟乙烯（PTFE）人工血管移植物（长3 cm，直径1 cm）中。将两只圆柱形PTFE人工血管移植物分别植入每只新西兰白兔的双侧髂嵴上（n = 16）。在每个PTFE腔室的侧面开一个2×0.5 cm的开口，以使腔室内的内容物与回肠的骨髓接触。腔室为空（A组和D组），填充I型胶原蛋白/羟基磷灰石珠（B组和C组）。在C组和D组中，每周通过经皮注射法将自体富血小板血浆（PRP）注入腔室。12周后，处死动物并取出腔室进行放射学和组织学分析。
在X线平片中，与其他组相比，C组腔室的骨组织工程化程度显著更高（平均钙化密度0.95，平均钙化面积61.83%）（P < 0.001）。在组织学检查中，C组中植入物被纤维血管组织向内生长逐渐替代。在腔室的所有部位，这些生物材料珠之间存在丰富的纤维血管网络。显示了这些珠子的降解以及降解基质周围新形成的毛细血管和类骨质。共聚焦显微镜下观察到的强烈绿色荧光证明了基质或降解基质中的持续钙化。在B组中，结构较松散，没有组织向内生长的迹象。在无支架组（A组和D组）中，腔室内仅显示纤维组织。
在本研究中，我们展示了一种可行的方法来制造满足临床需求的骨组织。通过使用I型胶原蛋白/羟基磷灰石凝胶珠基质并间歇性注射自体富血小板血浆，在体内动物模型中成功地从预先存在的骨边缘创建了具有纤维血管网络结构的特定三维骨组织。
