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.
ABSTRACT
Ethanol extract of Pleurotus eryngii (DC.) QUÉL has estrogen-like activities that protect against bone loss caused by estrogen deficiency. In the present study, we investigated the effect of P. eryngii on depression-like behavior and memory impairment in ovariectomized (OVX) rats. Immobility time during a forced swimming test was significantly longer for OVX rats than for sham-operated rats. The depression-like behavior in OVX rats was improved by long-term administration of the ethanol extract of P. eryngii (500 mg/kg body weight (b.w.)/d). Spatial memory impairment in OVX rats assessed by the Morris water maze test was also improved by P. eryngii extract without any effect on motility. These results suggested that P. eryngii extract has estrogen-like improvement activity against depression-like behavior and memory impairment in OVX rats. Additionally, increase in the amount of synaptosomal zinc after ovariectomy was inhibited by P. eryngii extract. Since zinc in synaptic vesicles is important for memory function and is linked to the pathophysiology of depression, normalization of zinc signaling would be involved in the beneficial effect of P. eryngii extract on neurological disorders after ovariectomy.
