Specific Effects of γ-Linolenic, Eicosapentaenoic, and Docosahexaenoic Ethyl Esters on Bone Post-ovariectomy in Rats
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Long chain polyunsaturated fatty acids (LCPUFAs) are involved in the regulation of bone metabolism. Increased dietary consumption of n-3, and possibly some n-6, LCPUFAs may limit postmenopausal bone loss. The aim of this study was to determine the effects on bone of specific fatty acids within the n-3 and n-6 LCPUFA families in ovariectomized (OVX) rats. Rats were OVX or sham-operated and fed either a control diet (OVX and sham) or a diet supplemented with 0.5 g/kg body weight/day of γ-linolenic (GLA), eicosapentaenoic (EPA), docosahexaenoic (DHA) ethyl esters or a mixture of all three (MIX) for 16 weeks. Bone mineral content (BMC), area, and density and plasma concentrations of insulin-like growth factor-I, vitamin D, selected biochemical markers of bone metabolism, and parathyroid hormone (PTH) were determined. The OVX-induced decrease in lumbar spine BMC was significantly attenuated by DHA but not by EPA or GLA supplementation or supplementation with a mixture of all three LCPUFAs. Endosteal circumferences of tibiae were significantly greater in DHA and EPA compared to OVX. Plasma C-terminal telopeptide of type I collagen and osteocalcin concentrations were not significantly different in the DHA group compared to OVX. Femur BMC decreased by a significantly greater amount in GLA than OVX, and final plasma PTH concentrations were significantly higher in GLA compared to all other groups. In conclusion, DHA ameliorated OVX-induced bone mineral loss. GLA exacerbated post-OVX bone mineral loss, possibly as a result of PTH-induced bone catabolism.
Keywordsγ-Linolenic acid Eicosapentaenoic acid Docosahexaenoic acid Ovariectomy Long chain polyunsaturated fatty acids Rats
This study was funded by Fonterra Brands Ltd., New Zealand. R. C. P. was the recipient of a TAD scholarship from the Tertiary Education Commission, New Zealand.
- 2.Watkins B, Seifert M (1996) Food lipids and bone health. In: McDonald R, Min D (eds) Food lipids and health. Marcel Dekker, New YorkGoogle Scholar
- 6.Yoshiko Y, Gonsalves P, Hiyama S, Uchida T, Maeda N, Aubin JE (2003) Activation of prostaglandin E receptor EP2 during the osteoprogenitor proliferation-differentiation transition is the major pathway mediating the anabolic effects of PGE2 on osteoblast development in rat calvaria cell cultures. Bone 32:S139–S139Google Scholar
- 12.Miller CC, Tang W, Ziboh VA, Fletcher MP (1991) Dietary supplementation with ethyl-ester concentrates of fish oil (n-3) and borage oil (n-6) polyunsaturated fatty-acids induces epidermal generation of local putative antiinflammatory metabolites. J Invest Dermatol 96:98–103PubMedCrossRefGoogle Scholar
- 16.Decaterina R, Cybulsky MI, Clinton SK, Gimbrone MA, Libby P (1994) The omega-3-fatty-acid docosahexaenoate reduces cytokine-induced expression of proatherogenic and proinflammatory proteins in human endothelial-cells. Arterioscler Thromb 14:1829–1836Google Scholar
- 17.Soyland E, Lea T, Sandstad B, Drevon A (1994) Dietary supplementation with very long-chain n-3 fatty-acids in man decreases expression of the interleukin-2 receptor (Cd25) on mitogen-stimulated lymphocytes from patients with inflammatory skin diseases. Eur J Clin Invest 24:236–242PubMedGoogle Scholar
- 24.Kruger M, Coetzer H, de Winter R, Gericke G, van Papendorp D (1998) Calcium, gamma-linolenic acid and eicosapentaenoic acid supplementation in senile osteoporosis. Aging Clin Exp Res 10:385–394Google Scholar
- 26.Claassen N, Potgieter HC, Seppa M, Vermaak WJH, Coetzer H, Vanpapendorp DH, Kruger MC (1995) Supplemented gamma-linolenic acid and eicosapentaenoic acid influence bone status in young male rats—effects on free urinary collagen cross-links, total urinary hydroxyproline, and bone calcium content. Bone 16:S385–S392CrossRefGoogle Scholar
- 34.National Research Council (1995) Nutrient requirements of laboratory animals, 4th rev ed. National Academy Press, Washington DCGoogle Scholar
- 35.Rahman M, Bhattacharya A, Banu J, Fernandes G (2005) Reduced bone loss by docosahexaenoic acid (DHA) than eicosapentaenoic acid (EPA) in ovariectomised mice. J Bone Miner Res 20:S127Google Scholar
- 36.Li Y, Reinwald S, Seifert M, Watkins B (2003) Dietary docosahexaenoic acid supplementation maintains bone mass in ovariectomised rats. Exp Biol Abstracts B321:188.110Google Scholar