Abstract:

BACKGROUND: Preliminary studies have proved that oral administration of simvastatin can improve the quality and speed of fracture healing.
OBJECTIVE: To investigate the effects of Kirschner wire followed simvastatin polylactic acid coatings on femoral fracture healing in ovariectomized rats.
METHODS: Forty 12-week-old health female Sprague-Dawley rats were randomly divided into four groups, fracture group, ovariectomized fracture group, polylactide group and simvastatin group. All the rats except those in the fracture group underwent bilateral ovariectomy to prepare the model of osteoporosis. The closed femur fractures of the rats were treated with Kirschner wire internal fixation 4 weeks later. The Kirschner wire in the polylactide group was coated with polylactide, and that in the simvastatin group was polylactide mixed with simvastatin (50 μg/implant). The Kirschner wires in the other groups were without treatment.
RESULTS AND CONCLUSION: Compared with the polylactide group, fracture line in the simvastatin group was less distincted, the periosteal reaction was fiercer, and the score of X-ray analysis was increased significantly (P < 0.05). Histopathological observation showed that new woven bone was more and arranged tightly and regularly in the simvastatin group. Immunohistochemical staining showed strong expression of bone morphogenetic protein-2 positive cells in the simvastatin group and the integrated optical density value was significantly higher than that of the polylactide group (P < 0.05), but the level of vascular endothelial growth factor in the simvastatin group was significantly lower than those of the polylactide group and model group (P < 0.05). The polylactide mixed with simvastatin coatings can promote the healing of osteoporotic hip fracture in ovariectomized rats.