Effects of polylactic acid copolymer/adipose-derived stem cells complex on the biomechanical properties after fracture healing in osteoporotic bone / 中国组织工程研究

ABSTRACT

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.