Abstract: BACKGROUND: Jiuxian Luohan Jiegu Decoction can promote blood circulation, remove blood stasis, reduce swelling, and relieve pain. However, its specific mechanism underlying tibial fractures has not yet been fully elucidated.
OBJECTIVE: To explore the effect of Miao medicine Jiuxian Luohan Jiegu Decoction on the osteogenic differentiation and fracture healing ability of rats with tibial fractures mediated by bone morphogenetic proteins (BMPs)/Smad signaling pathway. 
METHODS: Sixty Sprague-Dawley rats were randomly divided into a fracture group, a Miao medicine group, and a Panax notoginseng group. The Miao medicine group was given Jiuxian Luohan Jiegu Decoction (2 mL/kg) by gavage; the Panax notoginseng group was given the same volume of panax notoginseng powder      (1 mL/kg) by gavage; and the model group was given the same amount of distilled water by gavage, once a day, for 28 days in total. Alizarin red staining was used to measure osteogenic differentiation of bone marrow mesenchymal stem cells. RT-PCR and western blot were used to measure BMP-2, transforming growth factor-β, Smad1, and Smad2 at mRNA and protein levels. Three-point bending test was used to measure biomechanical indexes. Hematoxylin-eosin staining was used to detect bone tissue morphology. ELISA was used to measure serum vascular endothelial growth factor and insulin growth factor-1. 
RESULTS AND CONCLUSION: (1) Compared with the model group, the differentiated cells of the Miao medicine group and the Panax notoginseng group grew in multiple layers and formed focal shapes, and a large number of calcium nodules were formed. The Miao medicine group showed better effects than the Panax notoginseng group. (2) Compared with the model group, the mRNA levels of BMP-2, transforming growth factor-β, Smad1, and Smad2 were increased in the Panax notoginseng group and the Miao medicine group increased (P < 0.05). (3) The maximum load and stiffness of the panax notoginseng group and the Miao medicine group were higher than those of the model group (P < 0.05). (4) The bone trabeculae of the model group were thin, arranged disorderly, and relatively loosely, the space between the medullary cavities was large, and a large number of uncalcified chondrocytes appeared. Similar bone tissue morphology was found in the Panax notoginseng group and the Miao medicine group is similar, in which the bone trabecula was thicker, the medullary cavity space was reduced, the distribution was more orderly, and the chondrocytes were more ossified compared with those in the model group. (5) Compared with the model group, the expression levels of vascular endothelial growth factor and insulin growth factor-1 in the Panax notoginseng group and the Miao medicine group increased to a certain extent (P < 0.05). (6) Radiological observations showed that there were obvious fracture lines in the model group, while the fractured ends of the samples in the Panax notoginseng group and the Miao medicine group reached complete healing. However, the scab density at fractured ends of the Miao medicine group was slightly higher than that of the Panax notoginseng group. (7) To conclude, Miao medicine (Jiuxian Luohan Jiegu Decoction) can promote osteoblast differentiation and accelerate fracture healing. Its mechanism of action may be achieved by activating the BMPs/Smad signaling pathway.

Key words: Miao Medicine Jiuxian Luohan Jiegu Decoction, BMPs/Smad signaling pathway, osteogenic differentiation, fracture healing