Experimental study on the effect of warm acupuncture on the healing of bone nonunion in rats

BACKGROUND: Bone nonunion is a challenging clinical issue that hinders fracture healing. Warm acupuncture, as a traditional Chinese medicine therapy, has shown potential in promoting tissue repair, but its effect on bone nonunion healing and the underlying mechanism remain unclear. This study aims to investigate the effect of warm acupuncture on the healing of bone nonunion in rats and predict its potential mechanism. METHODS: Sprague-dawley (SD) rats were randomly divided into a blank control group (BC group), a tibial bone nonunion model group (M group), and a warm acupuncture treatment group (WA group). BC group was not treated. Bone nonunion modeling was performed on M and WA groups. After modeling, M group was tied up. WA group was treated with warm acupuncture after restraint, once a day for 4 weeks. After treatment, collected blood samples, performed Digital Radiography (DR), Micro computed tomography (Micro-CT), Hematoxylin-Eosin staining (HE staining) and assess the bone morphogenetic protein 2 (BMP-2) protein expression by Western blot. RESULTS: After treatment, the phosphorus (P), calcium (Ca), and alkaline phosphatase (ALP) levels and the BMP-2 protein expression level were significantly higher in WA group than in BC group and M group. The difference between WA group and M group in terms of fracture scab measurement was statistically significant. The recovery of fracture structure in WA group was better than that in M group. WA group was better than M group in bending strength, bending stiffness, bending load, bending deflection, bending moment and deflection. Bone volume fraction, trabecular thickness, and number of trabeculae were higher in WA group than in M group. CONCLUSION: Warm acupuncture can enhance the serum Ca, ALP, and P concentrations and increase the expression of BMP-2 in rats, thus improving bone scab production, promoting the healing of fractures and increasing the biomechanical strength in rats.