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Raloxifene and vitamin K2 combine to improve the femoral neck strength of ovariectomized rats.
Calcif Tissue Int. 2005 Aug; 77(2):119-26.CT

Abstract

We evaluated the skeletal effects of two osteoporosis therapies in an ovariectomized rat model, raloxifene and vitamin K2, as well as the vitamin K2 plus raloxifene (K + Ral) combination. In two studies, 6-month-old rats were ovariectomized, except for sham-ovariectomy controls (Sham), and dosed orally with vehicle, 30 mg/kg vitamin K2, 1 mg/kg raloxifene, or the combination of K + Ral for 6 weeks following surgery. Vitamin K2 had no effect on serum estrogen, low-density lipoprotein cholesterol (LDL-C), or urinary deoxypyridinoline levels, but slightly increased osteocalcin levels compared to Ovx. Raloxifene lowered total cholesterol, LDL-C, osteocalcin, and urinary deoxypyridinoline levels to below Ovx levels, while having no effect on estrogen levels. Raloxifene, but not vitamin K2, prevented ovariectomy-induced loss of bone in the distal femoral metaphysis and proximal tibial metaphysis, as did the K + Ral combination. Raloxifene, but not vitamin K2, partially prevented, loss of vertebral bone mineral density (BMD), whereas K + Ral had BMD greater than that of Ovx. Vitamin K2 increased bone formation rate to above Ovx, whereas raloxifene and K + Ral reduced bone formation rate to Sham levels. Vitamin K2 had no effect on eroded surface compared to Ovx, while raloxifene and K + Ral reduced eroded surface to Sham levels. Groups were not different in the BMD of femoral midshaft; however vitamin K2 was observed to increase periosteal mineralizing surface of the tibial shaft to above Ovx, while raloxifene reduced periosteal mineralizing surface toward Sham levels. Femoral neck strength was not different between groups, indicating no significant beneficial effect of either raloxifene or vitamin K2 at this site. However, K + Ral had reproducibly greater femoral neck strength than Ovx or Sham. Raloxifene, but not vitamin K2, partially prevented loss of lumbar vertebra strength; but K + Ral was not different from Sham or Ovx. Therefore, raloxifene and vitamin K2 had complementary effects on bone resorption and formation activities, respectively, resulting in a reproducible, significant improvement of femoral neck strength. These rat data suggest interesting therapeutic possibilities that may require clinical verification.

Authors+Show Affiliations

Department of Sports Medicine, Keio University School of Medicine, Tokyo, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16059775

Citation

Iwamoto, J, et al. "Raloxifene and Vitamin K2 Combine to Improve the Femoral Neck Strength of Ovariectomized Rats." Calcified Tissue International, vol. 77, no. 2, 2005, pp. 119-26.
Iwamoto J, Yeh JK, Schmidt A, et al. Raloxifene and vitamin K2 combine to improve the femoral neck strength of ovariectomized rats. Calcif Tissue Int. 2005;77(2):119-26.
Iwamoto, J., Yeh, J. K., Schmidt, A., Rowley, E., Stanfield, L., Takeda, T., & Sato, M. (2005). Raloxifene and vitamin K2 combine to improve the femoral neck strength of ovariectomized rats. Calcified Tissue International, 77(2), 119-26.
Iwamoto J, et al. Raloxifene and Vitamin K2 Combine to Improve the Femoral Neck Strength of Ovariectomized Rats. Calcif Tissue Int. 2005;77(2):119-26. PubMed PMID: 16059775.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Raloxifene and vitamin K2 combine to improve the femoral neck strength of ovariectomized rats. AU - Iwamoto,J, AU - Yeh,J K, AU - Schmidt,A, AU - Rowley,E, AU - Stanfield,L, AU - Takeda,T, AU - Sato,M, Y1 - 2005/07/28/ PY - 2004/11/28/received PY - 2005/04/04/accepted PY - 2005/8/2/pubmed PY - 2005/11/9/medline PY - 2005/8/2/entrez SP - 119 EP - 26 JF - Calcified tissue international JO - Calcif Tissue Int VL - 77 IS - 2 N2 - We evaluated the skeletal effects of two osteoporosis therapies in an ovariectomized rat model, raloxifene and vitamin K2, as well as the vitamin K2 plus raloxifene (K + Ral) combination. In two studies, 6-month-old rats were ovariectomized, except for sham-ovariectomy controls (Sham), and dosed orally with vehicle, 30 mg/kg vitamin K2, 1 mg/kg raloxifene, or the combination of K + Ral for 6 weeks following surgery. Vitamin K2 had no effect on serum estrogen, low-density lipoprotein cholesterol (LDL-C), or urinary deoxypyridinoline levels, but slightly increased osteocalcin levels compared to Ovx. Raloxifene lowered total cholesterol, LDL-C, osteocalcin, and urinary deoxypyridinoline levels to below Ovx levels, while having no effect on estrogen levels. Raloxifene, but not vitamin K2, prevented ovariectomy-induced loss of bone in the distal femoral metaphysis and proximal tibial metaphysis, as did the K + Ral combination. Raloxifene, but not vitamin K2, partially prevented, loss of vertebral bone mineral density (BMD), whereas K + Ral had BMD greater than that of Ovx. Vitamin K2 increased bone formation rate to above Ovx, whereas raloxifene and K + Ral reduced bone formation rate to Sham levels. Vitamin K2 had no effect on eroded surface compared to Ovx, while raloxifene and K + Ral reduced eroded surface to Sham levels. Groups were not different in the BMD of femoral midshaft; however vitamin K2 was observed to increase periosteal mineralizing surface of the tibial shaft to above Ovx, while raloxifene reduced periosteal mineralizing surface toward Sham levels. Femoral neck strength was not different between groups, indicating no significant beneficial effect of either raloxifene or vitamin K2 at this site. However, K + Ral had reproducibly greater femoral neck strength than Ovx or Sham. Raloxifene, but not vitamin K2, partially prevented loss of lumbar vertebra strength; but K + Ral was not different from Sham or Ovx. Therefore, raloxifene and vitamin K2 had complementary effects on bone resorption and formation activities, respectively, resulting in a reproducible, significant improvement of femoral neck strength. These rat data suggest interesting therapeutic possibilities that may require clinical verification. SN - 0171-967X UR - https://www.unboundmedicine.com/medline/citation/16059775/Raloxifene_and_vitamin_K2_combine_to_improve_the_femoral_neck_strength_of_ovariectomized_rats_ L2 - https://dx.doi.org/10.1007/s00223-004-0277-8 DB - PRIME DP - Unbound Medicine ER -