| Postmenopausal osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. The occurring rate and damage of postmenopausal osteoporosis is high in aged women, but the treatment is difficult. This article attempts to observe the effects of moderate intensity exercise on the serum level of nitric oxide (NO), estradiol (E2), osteocalcin, adiponectin, and leptin and the bone mineral density (BMD) in ovariectomized rats.In this paper, thirty 12 wk-old female Sprague-Dawley rats were randomly assigned to three groups: sham operation, ovariectomized (OVX) and treadmill exercise prevention group (OVX+EX). Surgical procedure was performed under anesthesia through bilateral skin incision at the lower back. Animals were allowed to recover for 7 days after surgery. Exercised-trained rats ran in the morning on a motorized treadmill 6 days per week. During the first week, animals were accustomed to exercise by running at low exercise intensity (10m/min at 0 % grade for 15-25min/d). The duration of training, speed were gradually increased to 60min/d and 18m/min by week 2, continuously training through the following weeks. At the end of the experiment, all the animals were weighted and killed, blood was collected for serum, and uterus and intra-abdominal fats were removed. NO content was tested by nitrate reductase method; E2 was tested by radioimmunoassay (RIA); osteocalcin, leptin and adiponectin levels were tested by enzyme-linked immunosorbent assay (ELISA). In addition, dual-energy x-ray absorptiometry instrument was used to detect the BMD of right femur and tibia.The results indicated: (1)The body weight, absolute weight of intra-abdominal fats and relative weight of intra-abdominal fats, serum leptin contents in OVX group is significantly higher than sham-operated group, but absolute weight of uterine and relative weight of uterine, the serum level of E2, osteocalcin, adiponectin were significantly lower than sham-operated group. After treatment with exercise for 12 weeks, the body weight and both the absolute and relative weight of intra-abdominal fat and the serum leptin contents in OVX+EX group is significantly lower than OVX group, whereas the levels of serum E2, osteocalcin was significantly higher than OVX group. In addition, no changes was found in serum adiponectin and uterus weight between OVX-EX and OVX group; (2) In femur, OVX resulted in a significant decrease of BMD in both proximal and distal metaphysis in contrast to no change was found in metaphysis. Exercise only exerted significant effects on proximal metaphysis. In tibia, OVX only resulted in a significant decrease of BMD in proximal metaphysis and exercise treatment had no effect on the three sites. (3) The serum content of NO decreased significantly after OVX and treatment with exercise exerted no effect. The activities of NOS were not significantly different between all groupsConclusion: (1) OVX resulted in significant increase of body weight, intra- abdominal weight and serum leptin level, these increase could be reversed by treatment exercise; (2) Exercise had no effect on serum content of NO in OVX rats; (3) The effect of exercise on BMD in OVX rats was site-dependent.
|
PDF Full Text Request