Anthocyanin-Rich Blackcurrant Extract Attenuates Ovariectomy-Induced Bone Loss in Mice

Although several animal and cell studies have indicated that blackcurrant anthocyanins exert antioxidative and anti-inflammatory properties, which could potentially improve bone mass, the effect of blackcurrant on bone health has not been reported yet. Thus, this study was aimed to evaluate the effect of blackcurrant anthocyanins on bone mass in an estrogen deficiency mouse model. Fourteen-week-old C57BL/6J mice (n=54) were ovariectomized or sham operated. The ovariectomized mice were divided into two groups, basal diet (OVX) or basal diet containing 1% anthocyanin-rich blackcurrant extract (OVX+BC), and sacrificed at 4, 8, and 12 weeks. Femoral bone mineral density (BMD) and trabecular bone volume by dual-energy X-ray absorptiometry and micro-computed tomography, respectively, and serum bone markers were measured. Ovariectomy significantly reduced BMD and trabecular bone volume at all time points (P<.05). Blackcurrant supplementation attenuated ovariectomy-induced bone loss measured by BMD and trabecular bone volume at 8 weeks (P=.055 and P=.057) and the effect was more pronounced at 12 weeks (P=.053 and P<.05). Ovariectomy and blackcurrant treatment did not alter serum biomarkers of bone formation and resorption. Bone marrow cells extracted from OVX mice significantly induced osteoclast-like (OCL) cell formation compared with cells from sham controls (P<.05). Blackcurrant treatment decreased the number of TRAP(+) OCL compared with OVX mice at 8 and 12 weeks (P<.05). Furthermore, blackcurrant supplementation reduced bone resorption activity when measured by resorption pit assay, compared with OVX group (P<.05). These results demonstrate that blackcurrant may be effective in mitigating osteoclast-induced postmenopausal bone loss.