Estrogen deficiency leads to various problems in different systems especially vascular systemand bone remodeling, producing vascular disease and osteoporosis. The objective of this study was toexamine roles of estradiol in postmenopausal induced-endothelial dysfunction and bone loss, theovariectomized rat model was used. Eighteen female Wistar rats were divided into three groups ofsham, Ovariectomized rats (OVX), and 17-estradiol treated-ovariectomized rat (OVXE2, 5g/kg/day;sc). At 3 weeks after the ovariectomized surgery, the number of leukocyte adhesion in bonepostcapillary venules (diameter = 15-30 um) of each group was determined by Intravital fluorescencevideo microscopy. Bone mass density (BMD) and bone formation marker were determined andrepresented by percentage of ash/dry matter and osteocalcin activity (using radioimmunoassay (RIA)),respectively. The results showed that in 3-wk OVX, leukocytes adhesion was significantly increasedcompared to their age-matched sham groups. Interestingly, 3-wk-OVXE2 leukocytes adhesion wassignificantly decreased. Besides, in 3-wk-OVXE2, the values of BMD was significantly increased andosteocalcin activity was significantly decreased as compared with 3-wk OVX. Therefore, our findingssuggested that hormone replacement therapy could effectively prevent bone microvascular dysfunctionand bone loss.
