Abstract: Objective: To investigate the effect of Antarctic krill oil (AKO) on fracture healing in an osteoporotic mouse model. Methods: Female C57BL/6J mice were ovariectomized to establish the animal model of osteoporosis. Then the mice were subjected to open fracture operation on the right tibial and randomly divided into four groups: control, osteoporotic fracture model, positive control and AKO groups. We dynamically observed the effect of AKO on serum biochemical indicators and callus histomorphology, microstructure and biomechanical properties at 5, 11, 24, 35 and 56 days post-fracture. In addition, we also investigated the effect of AKO on the expression of key genes involved in endochondrial ossification. Results: The results of enzyme-linked immunosorbent assay showed that AKO could significantly increase the serum levels of vascular endothelial growth factor (VEGF) and bone alkaline phosphatase. The HE staining and micro-computed tomography results showed that AKO could promote the transformation of cartilaginous callus into osseous callus, improved the microstructure of callus and accelerated callus remodeling. AKO could enhance biomechanical properties of bony callus. The quantitative real time polymerase chain reaction results showed that AKO significantly increased the mRNA expression of angiogenesis factors (VEGF, platelet derived growth factor and angiotensin 1) (P < 0.05), and decreased the expression of the genes associated with chondrocyte proliferation and hypertrophy (Aggrecan and Col10a) (P < 0.05). Furthermore, AKO significantly increased the mRNA expression of MMP-13 and osteogenesis-related genes (Col1a, OCN and bone morphogenetic protein (BMP-2)) (P < 0.05). These results suggested that AKO could accelerate the process of cartilage ossification and promote fracture healing by regulating the expression of key genes related to endochondral ossification. Conclusion: AKO can accelerate osteoporotic fracture healing and improve healing quality by promoting the process of cartilage ossification and callus remodeling.

Key words: Antarctic krill oil, osteoporosis fracture, fracture healing, cartilage ossification