背景:聚乳酸共聚物骨支架具有优异的生物降解性且易被塑造为三维立体支架,能促进骨组织和血管的生成、生长.目的:观察骨质疏松骨折后,聚乳酸共聚物复合脂肪干细胞对骨折愈合后生物力学的影响.方法:将60只SD大鼠随机分为4组,空白对照组不做任何处理;模型组切除双侧卵巢3个月后,制作双侧胫骨骨折模型;细胞治疗组切除双侧卵巢3个月后,制作双侧胫骨骨折模型,于骨折周围植入脂肪干细胞;联合治疗组切除双侧卵巢3个月后,制作双侧胫骨骨折模型,于骨折周围植入聚乳酸共聚物-脂肪干细胞复合体.治疗4周后,观察各组骨密度、骨痂厚度、生物力学参数及骨小梁微结构变化.结果与结论:①骨密度:模型组骨密度低于空白对照组(P<0.05);细胞治疗组、联合治疗组骨密度高于模型组(P<0.05),但低于空白对照组(P<0.05);联合治疗组骨密度高于细胞治疗组(P<0.05);②骨痂厚度:细胞治疗组、联合治疗组骨痂厚度高于模型组、空白对照组(P<0.05),且联合治疗组高于细胞治疗组(P<0.05);③生物力学测试:与空白对照组比较,模型组破坏载荷、极限应力、剪切强度、弹性模量降低(P<0.05),剪切应变升高(P<0.05);与模型组比较,细胞治疗组、联合治疗组破坏载荷、极限应力、剪切强度、弹性模量升高(P<0.05),剪切应变降低(P<0.05),且以联合治疗组改变更显著(P<0.05);④骨小梁微结构:模型组骨小梁排列紊乱,间距增大,甚至出现断裂和陷窝;细胞治疗组、联合治疗组骨小梁数目增多且增粗增厚,间距减小,陷窝减少;⑤结果表明:聚乳酸共聚物复合脂肪干细胞治疗骨质疏松骨折可明显改善愈合后骨组织的生物力学参数.%BACKGROUND: Polylactic acid copolymer bone scaffold has excellent biodegradability, and it is easy to be shaped and can promote the formation and growth of bone tissue and blood vessel.OBJECTIVE: To observe the effects of adipose-derived stem cells(ADSCs)/poly(lactic-co-glycolic acid) (PLGA) complex on the biomechanical properties after fracture healing in osteoporotic bone.METHODS: Sixty Sprague-Dawley rats were randomly divided into four groups: blank control group received no treatment; the bilateral tibial fracture model was made after 3 months of bilateral ovarian resection in model group; the bilateral tibial fracture model was made and ADSCs were implanted into the bone after 3 months of bilateral ovarian resection in cell therapy group; the bilateral tibial fracture model was made and the PLGA/ADSCs complex was implanted after 3 months of bilateral ovarian resection in combined treatment group.The bone mineral density, callus thickness, biomechanical parameters and the microstructure of the trabecular bone were detected.RESULTS AND CONCLUSION: (1) The bone density: The bone density of the model group was significantly lower than that of the blank control group (P < 0.05); the bone mineral density of the cell therapy group and the combined treatment group was higher than that of the model group (P < 0.05), but lower than that of the control group (P < 0.05); and the bone mineral density of the combination treatment group was higher than that of the cell therapy group (P < 0.05). (2)Thickness of the callus: The thickness of the callus in the cell therapy group and combined treatment group was higher than that of the model group and blank control group (P < 0.05); moreover, the thickness of the callus in the combined treatment group was higher than that of the cell therapy group (P < 0.05). (3) Biomechanical test: The failure load, stress and shear strength, elastic modulus were decreased in the model group compared with the blank control group (P < 0.05), while the shear strain increased (P < 0.05). Compared with the model group, the failure load, ultimate stress, shear strength, elastic modulus were increased in the cell therapy group and combined treatment group (P < 0.05), and the shear strain was decreased (P < 0.05). Moreover, the combined treatment group showed more changes in these biomechanical parameters (P < 0.05). (4) The trabecular bone microstructure: The model group presented with trabecular derangement, spacing increases, and even fracture and lacuna. After ADSCs or ADSCs/PLGA transplantation,the trabecular bones increased in number, thickness, and spacing, and the number of lacunae reduced. In conclusion,ADSCs combined with PLGA in the treatment of osteoporotic fracture can significantly improve the biomechanical parameters of bone tissue after healing.
展开▼
