In the current study, we investigated the improvement of phosphorylated peptides from Antarctic krill Euphausia superba (PP-AKP) on osteoporosis in ovariectomized rats. PP-AKP was supplemented to ovariectomized Sprague-Dawley rats for 90 days. The results showed that PP-AKP treatment remarkably prevented the reduction of bone mass and improved cancellous bone structure and biochemical properties. PP-AKP also significantly decreased serum contents of tartrate-resistant acid phosphatase (TRACP), cathepsin K (Cath-k), matrix metalloproteinases-9 (MMP-9), deoxypyridinoline (DPD), C-terminal telopeptide of collagen I (CTX-1), Ca, and P. Mechanism investigation revealed that PP-AKP significantly increased the osteoprotegerin (OPG)/receptor activator of nuclear factor κB ligand (RANKL) ratio in mRNA expression, protein expression, and serum content. Further research suggested that NF-κB signaling pathways were inhibited by suppressing the mRNA and protein expressions of nuclear factor of activated T-cells (NFATc1) and tumor necrosis factor receptor-associated factor 6 (TRAF6), diminishing the mRNA expression and phosphorylation of nuclear factor κB p65 (NF-κB p65), three key transcription factors in NF-κB pathways. These results suggest that PP-AKP can improve osteoporosis by inhibiting bone resorption via suppressing the activation of osteoclastogenesis related NF-κB pathways.
Keywords: antarctic krill; bone mass; bone resorption; phosphorylated peptides; receptor activator of nuclear factor κB.