Observing The Change Of Bone Trabecula During The Process Of Reduction Of The Athletic Bone Mass With Micro-ct

Objective:1. To establish the model of low bone mass by female SD rats which were trained by long-time increasingly large load.2. By modeling the process in the rat vaginal cytology, bone density scans, as well as the Micro-CT scanning of trabecular bone micro-structural changes as well as structural features, explore the long-term incremental load training of rats mechanism of micro structural changes in bone.Method:Will be 225 three-month-old female SD rats were randomly divided into control group 105 and exercise group 120. Exercise group rats Incremental treadmill training, no training in control rats. And four days a week all the rats were vaginal cytology were observed estrous cycle. The total training period of 17 weeks, were sacrificed before the whole-body bone mineral density scan and record the first 4 weeks,9 weeks, the first 11 weeks,15 weeks, the first 17 weeks of set derived time periods, respectively, in each time period random sampling exercise group 2 and control group as a sample of rats, five lumbar vertebrae out of its full removal of muscle and adipose tissue after the Micro-CT scan analysis of the microscopic structure of bone and its three-dimensional image data to summarize the characteristics and laws.Results:1. Bone mineral density scan results showed that:15 weeks before the exercise group and the control group was not statistically significant change in bone mineral density, exercise group for 15 weeks and 17 weeks of bone mineral density than the control group is significantly lower (P<0.01).2. Rat vaginal cytology showed:control group, no abnormal changes in rat estrous cycle, while the 9-week exercise group rats exhibited a suppression, and increased with the amount of exercise,11 weeks,15 weeks,17 weeks of exercise rats estrous cycle, inhibition is more severe, eventually leading to estrous cycle disorder.3. Micro-CT can clearly observe the microstructure of bone tissue, and can be obtained by binarization of the images in three-dimensional image of the systematic generation, are three-dimensional structure of rat lumbar images.4. Obtained three-dimensional microstructure of bone samples for testing specific parameters are as follows:bone volume fraction (BV/TV), bone surface area volume ratio (BS/BV), trabecular thickness (Tb·Th), trabecular bone gap (Tb·SP), trabecular number (Tb·N), structure model index (SMI). Experiment,4 weeks,9 weeks, two sets of parameters were increased to varying degrees, and the exercise group were significantly; 11 weeks,15 weeks, 17 weeks of exercise significantly reduced set of parameters. At the same time there are also parameters of the control group decreased, but the trend has slowed down significantly compared with the control group.Conclusions:1. Through 17 weeks of continuous incremental load of high-intensity training, sports modeling low bone mass in rats is feasible.2. By modeling the process on bone mineral density (BMD), bone volume fraction (BV/TV), bone surface area volume ratio (BS/BV), trabecular thickness (Tb·Th), trabecular bone gap (Tb·SP), trabecular number (Tb·N), structure model index (SMI) monitoring, that:amount of load exercise can increase bone density, increase bone mass; long-term high-load training will lead to decreased bone density, reducing bone mass.3. By modeling the process-related indicators for the detection, analysis that long-term training in rats Incremental changes in three-dimensional structure of bone micro-mechanisms: long-term high-intensity training has made the female rat estrous cycle disorder, the hypothalamus-pituitary-gonadal axis function inhibited, leading to lower estrogen levels, thereby enabling the enhanced role of osteoclasts, and new bone formation is weakened or even rejection, ultimately lowering the volume of bone formation.