Abstract: Objective: Peptides from Antarctic krill (AKP) were isolated from an enzymatic hydrolysate of Antarctic krill powder to explore its effect and underlying mechanism on fracture healing in mice. Methods: Female C57BL/6 mice underwent surgery for open fracture of the right tibia and were randomly divided into model control, low-dose (200 mg/kg mb) and high-dose (400 mg/kg mb) AKP groups. At 5, 10 and 21 days after surgery, samples were taken to dynamically analyze the effects of AKP on serum biochemical parameters, epiphyseal morphology and the transcription of the key genes related to endochondral ossification. Results: AKP could significantly increase the concentration of transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF) and collagen type I (Col1α) in serum (P < 0.05), and promote the formation of fibrous callus, the formation and transformation of cartilage callus and the formation and reconstruction of sclerotic callus in a dose-dependent manner. AKP also significantly up-regulated the mRNA transcription levels of early chondrocyte differentiation factor (SOX9 and Col10α), middle and late angiogenic genes (VEGF and Ang1), cartilage matrix degradation factor (MMP13) and bone formation-related genes (Col1α, OCN and TGF-β). Conclusion: AKP can promote fracture healing by accelerating the process of endochondral ossification.

Key words: peptides from Antarctic krill; fracture healing; histomorphology; endochondral ossification