No abstract

Abstract. Menopause is associated with increased oxidative stress, which serves a role, in part, in the pathogenesis of postmenopausal bone loss. Fruits and vegetables are rich in antioxidative nutrients and phytochemicals. Berries are a natural source of anthocyanins, and their intake may improve bone health. The aim of the present study was to determine the effect of an anthocyanin-rich bilberry extract (VME) on bone metabolism in an ovariectomized (Ovx) rat. Female Sprague-Dawley rats (12 weeks old) were randomly divided into the following four groups: Baseline, Sham, Ovx and Ovx+VME (n=8-12 rats per group). Rats in the Baseline group were sacrificed immediately, while those in the other groups were subjected to either sham operation (Sham) or bilateral Ovx (Ovx and Ovx+VME). Rats in the Ovx+VME group were administered VME daily at a dose of 500 mg/kg body weight. At 8 weeks after surgery, bone mass and bone histomorphometry were evaluated. The femur bone mineral density (BMD) in the Ovx group was significantly lower than that in the Sham group (P<0.01). Supplementation of VME in the Ovx rats did not result in an increase in BMD. Histomorphometric analyses revealed that Ovx resulted in decreased measures of bone volume and trabecular number and increased measures of osteoid volume, mineralizing surface and bone formation rates (all P<0.01), whereas VME had no significant effects on these parameters. The present findings indicate that VME did not alter bone metabolism in Ovx rats, suggesting that consumption of VME may not be helpful in preventing postmenopausal bone loss.

No abstract

Although estrogen possesses both pro- and anti-oxidant properties, its overall role in oxidative stress among women remains unclear, particularly since the influence of exogenously administered estrogen during previous studies differed by dose, administration route, and estrogen type. The aim of this study was to elucidate the effects of endogenous estrogen on oxidative stress in women. Thus, we performed a non-interventional observational study of healthy postmenopausal (n = 71) and premenopausal (n = 72) female volunteers. Serum levels of derivatives of reactive oxygen metabolites (d-ROMs, which are collectively a marker of oxidative stress), as well as the biological antioxidant potential (BAP, an indicator of antioxidant capacity), were compared between (1) pre- versus post-menopausal women, and (2) premenopausal women in early follicular versus mid-luteal phases of their menstrual cycles. We found that serum d-ROMs and BAP values in postmenopausal women were significantly higher than those in premenopausal women. Moreover, the d-ROM levels were significantly correlated with serum copper concentrations. However, neither d-ROMs nor BAP values were significantly affected by the menstrual cycle phase, although changes in d-ROMs between the follicular and luteal phases were significantly correlated with copper concentration shifts. These data indicate that postmenopausal hypoestrogenism is associated with elevated oxidative stress, although regular fluctuations of estrogen levels during the menstrual cycle do not influence oxidative stress.