title: Effects of the combination of vitamin K and teriparatide on the bone metabolism in ovariectomized rats.
abstract: The purpose of the present study was to evaluate the combined effects of vitamin K (VK) and teriparatide (TPTD) on bone mineral density (BMD), mechanical strength and other parameters for bone metabolism using a rat ovariectomized osteoporosis model. Ovariectomized female Sprague-Dawley rats were administered with VK (an oral dose of 30 mg/kg/day), TPTD (a subcutaneous dose of 30 µg/kg, three times a week) or a combination for 8 weeks. Thereafter, serum levels of γ-carboxylated osteocalcin (Gla-OC) were quantitated by ELISA; BMD and mechanical strength were measured by computed tomography and biomechanical testing, respectively at the femoral metaphysis. Additionally, histomorphometry was performed using the toluidine blue-stained coronal sections of distal femur. The combination of VK and TPTD clearly increased the serum levels of Gla-OC (a specific marker for bone formation) and osteoblast surface (the number of osteoblasts attaching with the surface of cancellous bone), compared to VK or TPTD alone. In addition, the combination of the two agents improved the BMD and bone strength of the femur in the ovariectomized rats, compared to VK or TPTD alone. Taken together, these findings suggest that the treatment with VK and TPTD may have a therapeutic advantage over VK or TPTD monotherapy for postmenopausal osteoporosis, possibly by enhancing the bone formation through the actions on OC and osteoblasts.
authors.affiliation: Department of Medicine for Motor Organs, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Nana
authors.initials: N
authors.lastname: Nagura
authors.affiliation: Department of Medicine for Motor Organs, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Komatsu
authors.affiliation: Department of Bio-Engineering, Juntendo University Institute of Casualty Center, Izunokuni, Shizuoka 410-2295, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Iwase
authors.affiliation: Department of Host Defense and Biochemical Research, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoda
authors.affiliation: Department of Medicine for Motor Organs, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Ohbayashi
authors.affiliation: Department of Host Defense and Biochemical Research, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Nagaoka
authors.affiliation: Department of Medicine for Motor Organs, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kaneko
keywords: bone metabolism; osteocalcin; ovariectomized rats; teriparatide; vitamin K