Abstract
Glucocorticoids are the leading cause of secondary osteoporosis. In the current study, the in vivo effects of Antarctic krill (Euphausia superba) oil (AKO) on dexamethasone-treated mice were investigated. Results showed that AKO significantly prevents bone loss, as evidenced by improved bone mineral density, biomechanical strength, and cancellous bone microstructure. Fluorescence double-labeling of femur showed that AKO induces new bone formation. Toluidine blue staining of marrow cavity indicated that AKO increases the number of trabecula, and decreases the generation of adipose cells. Runt-related transcription factor 2 (Runx2) and Peroxisome proliferator-activated receptor γ (PPARγ) are the switches for osteogenic and adipogenic differentiation of bone marrow mesenchymal stem cells, respectively. AKO significantly promoted the expression of Runx2 protein, and reduced PPARγ expression in bone tissue. Furthermore, AKO increased the mRNA expression of osteogenesis-related genes and decreased the expression of adipogenesis-related genes. In conclusion, AKO improved glucocorticoid-induced osteoporosis via promoting bone formation.