Inhibitory Effect of Vitamin K2 (Menatetrenone) on Bone Resorption in Ovariectomized Rats: A Histomorphometric and Dual Energy X-Ray Absorptiometric Study

To clarify how vitamin K2 prevents bone loss in vivo, it was given to ovariectomized 20-week-old rats for 2 weeks. Bone mineral density (BMD) in the whole femur and in 7 specific portions (FI to F7 from the proximal to the distal end) was determined by dual-energy X-ray absorptiometry, and histomorp...

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Bibliographic Details
Published in:Japanese journal of pharmacology 1999, Vol.80(1), pp.67-74
Main Authors: Yasuhiro, Akiyama, Kuniko, Hara, Masatoshi, Kobayashi, Takashi, Tomiuga, Tetsuya, Nakamura
Format: Article
Language:English
Subjects:
Absorptiometry, Photon
Animals
Bone Density - drug effects
Bone mineral density
Bone Resorption
Female
Femur
Hemostatics - pharmacology
Histomorphometry
Osteoclast number
Ovariectomy
Rats
Rats, Inbred F344
Tibia
Vitamin K - analogs & derivatives
Vitamin K - pharmacology
Vitamin K 2 - analogs & derivatives
Vitamin K2
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Summary:To clarify how vitamin K2 prevents bone loss in vivo, it was given to ovariectomized 20-week-old rats for 2 weeks. Bone mineral density (BMD) in the whole femur and in 7 specific portions (FI to F7 from the proximal to the distal end) was determined by dual-energy X-ray absorptiometry, and histomorphometry was also performed in proximal tibial metaphysis. Ovariectomy (OVX) resulted in significant decreases in the BMD in the whole femur and the FI, F2, F6 and F7 portions. Histomorphometrical analysis of the tibia showed that the bone volume / tissue volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) were decreased, while trabecular separation (Tb.Sp) and osteoclast number / bone surface (Oc.N/BS) were increased by OVX. The parameters for bone formation were not changed by OVX. These data indicate that the bone loss within 2 weeks is due to the enhancement of bone resorption. Vitamin K2 at 50 mg/kg inhibited the decrease in the BMD of the whole femur together with the F6 and F7 portions. Vitamin K2 also inhibited the decrease in Tb.N and the increases in Tb.Sp, Oc.N/BS and osteoclast surface / bone surface (Oc.S/BS) caused by OVX. These results suggest that vitamin K2 prevents bone loss through the inhibition of bone resorption and osteoclast formation in vivo.
ISSN:0021-5198
1347-3506
DOI:10.1254/jjp.80.67