Biomechanical researches on tissue engineering bone constructed by deproteinated bone / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study biomechanical changes of newly formed bones 24 weeks after repairing large defects of long bones of goats using heterogeneous deproteinated bone (DPB) prepared by modified methods as an engineering scaffold.</p><p><b>METHODS</b>According to a fully randomized design, 18 goats were evenly divided into three groups: normal bone control group (Group A), autologous bone group (Group B) and experimental group (Group C). Each goat in Groups B and C were subjected to the periosteum and bone defect at middle-lower part of the right tibia (20% of the whole tibia in length), followed by autologous bone or DPB plus autologous MSCs + rhBMP2 implantation, respectively and semi-ring slot fixation; while goats in Group A did not perform osteotomy. At 24 weeks after surgery, biomechanical tests were carried out on the tibias.</p><p><b>RESULTS</b>At 24 weeks after surgery, the results of anti-compression test on tibias in three groups were recorded by a functional recorder presented as linear pressure-deformation curve. The shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values were 10.74 MPa+/-1.23 MPa, 10.11 MPa+/-1.35 MPa and 10.22 MPa+/-1.32 MPa and fracture compression rates were 26.82%+/-0.87%, 27.17%+/-0.75% and 28.22%+/-1.12% in Groups A, B and C, respectively. Comparisons of anti-compression ultimate pressures and fracture compression rates among three groups demonstrated no significant difference (P(AB) equal to 0.415, P(BC) equal to 0.494). Three-point anti-bend test on tibias was recorded as load-deformation curves, and the shapes of the curves and their change tendency were similar among three groups. The ultimate pressure values of the anti-bend test were 481.52 N+/-12.45 N, 478.34 N+/-14.68 N and 475.62 N+/-13.41 N and the fracture bend rates were 2.62 mm+/-0.12 mm, 2.61 mm+/-0.15 mm and 2.81 mm+/-0.13 mm in Groups A, B and C, respectively. There was no significant difference between groups (P(AB) equal to 0.7, P(BC) equal to 0.448). The ultimate anti-torsion torque values were 6.55 Nm+/-0.25 Nm, 6.34 Nm+/-0.18 Nm and 6.42 Nm+/-0.21 Nm and fracture torsion rates were 29.51 degree+/-1.64degree, 28.88 degree+/-1.46 degree and 28.81 degree+/-1.33 degree in Groups A, B and C, respectively. There was no significant difference between groups (P(AB) equal to 0.123, P(BC) equal to 0.346).</p><p><b>CONCLUSIONS</b>The biomechanical characteristics of newly formed bones from heterogeneous DPB for repairing large segmental long bone defect are comparable to those of normal bones and autologous bones. DPB has the potential for clinical usage as bone graft material.</p>

Properties of deproteinized bone for reparation of big segmental defect in long bone / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To explore suitable scaffold material for big segmental long bone defect by studying the properties of the prepared deproteinized bone.</p><p><b>METHODS</b>Cancellated bone were made as 30 mm x mm x 3 mm bone blocks from inferior extremity of pig femur along bone trabecula. The deproteinized bone was prepared with an improved method. Their morphological features, components, cell compatibility, mechanical and immunological properties were investigated respectively.</p><p><b>RESULTS</b>Deproteinized bone maintained natural reticular pore system. The main organic material is collagen I and inorganic composition is hydroxyapatite. It has good mechanical properties, cell adhesion rate and histocompatibility.</p><p><b>CONCLUSION</b>This deproteinized bone can be applicable as scaffold for reparation of big segmental defect in long bone.</p>

Preparation and physicochemical properties of scaffold materials of heterogeneous deproteinized bone / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To prepare and observe the physicochemical properties of scaffold materials of heterogeneous deproteinized tissue-engineered bone.</p><p><b>METHODS</b>Deproteinized bone was made through a series of physicochemical treatments in pig ribs and analyzed with histological observation, scanning electron microscopy, infrared spectrum, X-ray diffraction and energy dispersive analysis, Kjeldahl determination and mechanics analysis.</p><p><b>RESULTS</b>Interstitial collagen fiber was positive and mucin was negative in deproteinized bone, but, both were positive in fresh bone. Deproteinized bone maintained natural pore network. Its pore size was 472.51 micromolar+/-7.02 micromolar and the porosity was 78.15%+/-6.45%. The results of infrared spectrum showed that collagen was present in deproteinized bone. Both fresh and deproteinized bone had curve of hydroxyapatite. The Ca/P ratios were 1.71+/-0.95 and 1.68+/-0.76 (P larger than 0.05), and the protein contents were 26.6%+/-2.23% and 19.1%+/-2.14% (P less than 0.05) in fresh and deproteinized bone, respectively. There was no significant difference of destruction load under compression and maximal destruction load between fresh and deproteinized bone (P larger than 0.05). The elastic modulus was higher in deproteinized bone than that in fresh bone (P less than 0.05).</p><p><b>CONCLUSIONS</b>Physicochemical properties and mechanic strength of deproteinized tissue-engineered bone meet the demands of ideal scaffold materials. But, its immunogenicity should be observed through further experiments for its clinical applications.</p>