Vitamin K2 analog menaquinone-7 shows osteoblastic bone formation activity in vitro

An increasing number of studies have shown that vitamin K may play a critical role in metabolism of bone. However, the anabolic effect of MK-7 on promoting bone formation needs to be further investigated. The present study investigates the effect of MK-7 on osteoblastic bone formation in femoral-diaphyseal and -metaphyseal tissues of 4-week-old rats (n=18). The rat tissue was cultured in Dulbecco’s modified Eagle’s medium supplemented with MK-7 (10-6M). The activity of alkaline phosphatase DNA content, and calcium content in diaphyseal and metaphyseal tissues were used as osteogenesis markers. The study showed that treatment with MK-7 significantly increased alkaline phosphatase activity, DNA content, and calcium content in the cultured diaphyseal and metaphyseal tissue; however, the activity was inhibited in the presence of epoxomicin (10-6 M). Culture of human osteoblastic cells SAOS-2 for 24 h in a serum-free medium containing MK-7 (10-6M) resulted in increased alkaline phosphatase activity, osteocalcin content, and DNA content, and the reaction was completely inhibited in presence of by epoxomicin. The study results indicate that MK-7 has a stimulatory effect on bone tissue and osteoblastic SAOS-2 cells in vitro and further clinical studies are required to pave way for the use of MK-7 in bone formation.