Calcium Citrate Supplement With Vitamin D3 and/or Vitamin K2 Promoted Bone Formation Effects in Zebrafish

Objectives: Bone metabolism is a dynamic equilibrium process, which is realized through bone formation and bone resorption. When the rate of bone resorption is greater than the rate of bone formation, osteoporosis is easily caused. Studies showed that vitamin D3 (VD3) supplementation could enhance the absorption rate of calcium in the intestine and increase the amount of calcium in the body, while vitamin K2 (VK2) could balance bone tissue metabolism, promote bone formation and inhibit bone resorption. In summary, both VD3 and VK2 have a positive effect in slowing bone loss, however, it was still unclear that whether there is synergistic potential of these two vitamins to promote bone health. The aim of this study is to assess synergistic effect of these two vitamins in zebrafish models. Methods: In this study, osteoblast-specific transcription factor green fluorescent zebrafish model was used to verify the synergistic potential of VD3 and/or VK2 on calcium-promoting bone action (including enhancing the fluorescence intensity of zebrafish head bone and increasing the expression of osteoblast-specific genes). Statistical analysis was performed using the ANOVA test. Values of P< 0.05 were considered statistically significant. Results: Our results showed that, compared with calcium citrate alone, calcium citrate combined with VD3 could effectively promote the expression of bone-related genes (alkaline phosphatase (P< 0.01), Runx2a (P< 0.01), osteocalcin (P< 0.01) and SP7 (P< 0.01)). It suggested that VD3 can significantly promote the effect of calcium in promoting osteoblast maturation and differentiation and promoting bone calcium deposition. In addition, the combination of calcium citrate with VD3 and VK2, compared with the combination of calcium citrate with VD3, can significantly increase the fluorescence intensity of zebrafish skulls (P< 0.05) and promote the expression of osteocalcin genes (P< 0.001). It indicated that VK2 can furtherly promote osteogenic differentiation and bone mineralization, and enhance the bone promoting effect of VD3. Conclusions: In summary, the results of this study suggested that both VD3 and VK2 can promote the role of calcium in promoting bone, and VD3 and VK2 may have the potential to synergistically enhance calcium absorption into bone, thereby improving human bone health. Funding Sources: Heath and Happiness (H&H) China Limited.