Bone Abstracts

Background: Resveratrol (RSV), a natural polyphenolic compound, stimulates osteoblasts and inhibits osteoclast activation in vitro. Conflicting results have emerged from short-term studies in rodents but a recent study in men suggests a positive effect on BMD.

Aim: To evaluate effects of short- and long-term high-dose RSV supplementation on bone in immobilized and non-immobilized rats.

Methods: A total of 72 female Wistar rats were randomly allocated to six groups. Two baseline groups (BSL_PD and BSL_Rsv) underwent short-term diet-intervention only, being fed a phytoestrogen-deficient diet (PD) or a RSV diet (600 mg/kg body weight/day) for 4 weeks before sacrifice. Four groups (IMMOB_PD and IMMOB_Rsv, and MOB_PD and MOB_Rsv) were injected in the right hindlimb with either botulinum toxin (BTX) (immobilized) or saline (non-immobilized), and fed either a PD diet or a RSV diet 4 weeks pre-injection and six weeks post-injection (long-term diet intervention) before sacrifice. DXA, μCT, and biomechanical tests were used for evaluation.

Results: Short-term RSV treatment did not affect the measured bone parameters, whereas long-term RSV exposure had a consistent negative impact on non-immobilized rats (MOB_Rsv versus MOB_PD) (results presented as mean percent difference with 95% CI); aBMD (−4.6% [−7.95; −1.25]%, P=0.009), distal femoral Tb.N (−12.1% [−21.4; −2.9]%, P=0.01), Tb.Sp (+17.4% [2.4; 31.9]%, P=0.03), and BV/TV (−11.4% [−23.6; 0.9]%, P=0.07). In addition, RSV reduced femoral mid-diaphyseal three-point bending strength (−9.1% [−17.0; −1.2]%, P=0.03) and stiffness (−8.7% [−17.2; −0.23]%, P=0.04). BTX-induced immobilization resulted in significant bone loss and reduced bone strength, and RSV supplementation was unable to prevent this.

Conclusion: Long-term high-dose RSV reduced bone mass and strength and did not prevent immobilization-induced bone loss.