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Evidence-Based Complementary and Alternative Medicine
Volume 3 (2006), Issue 3, Pages 339-348
http://dx.doi.org/10.1093/ecam/nel019
Original Article

Royal Jelly Prevents Osteoporosis in Rats: Beneficial Effects in Ovariectomy Model and in Bone Tissue Culture Model

1Department of Dental Hygiene, Fukuoka College of Health Sciences, Fukuoka, Japan
2Department of Dental Engineering, Section of Bioengineering, Fukuoka Dental College, Fukuoka, Japan
3Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
4Institute for Health Science, Yamada Apiculture Center Inc., Okayama, Japan
5Philadelphia Biomedical Research Institute, King of Prussia, PA, USA

Received 15 March 2006; Accepted 16 March 2006

Copyright © 2006 Saburo Hidaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Royal jelly (RJ) has been used worldwide for many years as medical products, health foods and cosmetics. Since RJ contains testosterone and has steroid hormone-type activities, we hypothesized that it may have beneficial effects on osteoporosis. We used both an ovariectomized rat model and a tissue culture model. Rats were divided into eight groups as follows: sham-operated (Sham), ovariectomized (OVX), OVX given 0.5% (w/w) raw RJ, OVX given 2.0% (w/w) RJ, OVX given 0.5% (w/w) protease-treated RJ (pRJ), OVX given 2.0% (w/w) pRJ, OVX given 17β-estradiol and OVX given its vehicle, respectively. The Ovariectomy decreased tibial bone mineral density (BMD) by 24%. Administration of 17β-estradiol to OVX rats recovered the tibial BMD decrease by 100%. Administration of 2.0% (w/w) RJ and 0.5–2.0% (w/w) pRJ to OVX rats recovered it by 85% or more. These results indicate that both RJ and pRJ are almost as effective as 17β-estradiol in preventing the development of bone loss induced by ovariectomy in rats. In tissue culture models, both RJ and pRJ increased calcium contents in femoral-diaphyseal and femoral-metaphyseal tissue cultures obtained from normal male rats. However, in a mouse marrow culture model, they neither inhibited the parathyroid hormone (PTH)-induced calcium loss nor affected the formation of osteoclast-like cells induced by PTH in mouse marrow culture system. Therefore, our results suggest that both RJ and pRJ may prevent osteoporosis by enhancing intestinal calcium absorption, but not by directly antagonizing the action of PTH.