Synergistic attenuation of ovariectomy-induced bone loss by combined use of fish oil and 17β-oestradiol. Issue 4 (14th March 2017) - Jin, Youri
Abstract: Oestrogen and n -3 PUFA, especially EPA and DHA, have been reported to have beneficial effects on bone loss. Thus, the purpose of the present study was to investigate the synergistic bone-protective mechanism of combined treatments of EPA+DHA supplementation and oestrogen injection in ovariectomised rats. Rats were fed a modified American Institute of Nutrition-93G diet with 0 %, 1 % or 2 % n -3 PUFA (EPA+DHA) relative to the total energy intake for 12 weeks. Rats were surgically ovariectomised at week 8, and after a 1-week recovery period rats were injected with either 17 β -oestradiol-3-benzoate (E2 ) or maize oil for the last 3 weeks. Combined use of n -3 PUFA and E2 synergistically increased femoral cortical bone volume, bone mineral content and the bone expression of runt-related transcription factor 2 (RUNX2), but decreased the bone expression of IL-1 β . Both n -3 PUFA and E2 decreased the bone expressions of IL-7, TNF- α and PPAR- γ, and increased the bone expression of oestrogen receptor- α . n -3 PUFA in the presence of E2 and E2 alone significantly decreased the bone expressions of IL-1 β and IL-6 and increased the bone expression of RUNX2. E2 significantly decreased the serum levels of bone turnover markers and the bone expression of receptor activator of NF- κ B ligand, but decreased the bone expression of osteoprotegerin. The combined use of n -3 PUFA and E2 exerted synergistic bone-protective efficacy through up-regulation of RUNX2, an essential transcription factor for bone formation, as well as the suppression of bone-resorbing cytokine IL-1 β .