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Study On The Changes Of Bone In Exercise-induced Estrous Cycle Inhibited Female Rats And The Mechanisms

Posted on:2006-07-14Degree:DoctorType:Dissertation
Country:ChinaCandidate:L GaoFull Text:PDF
GTID:1117360152493112Subject:Human Movement Science
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Puberty is the key time in which bone increase rapidly. If people carry on physical activity in puberty, bone mass will accelerate. But high intensity training would lead to athlete secondary amenorrhea(ASA), therefore endurance athlete always put up high athlete secondary amenorrhea rate. Lots of literature reported the peak bone mass of athlete with amenorrhea was very lower than that of control young people. The peak bone mass is correlation with the probability of osteoporosis. Now there are a lot of literature that report the happen rate of osteoporosis in athlete with amenorrhea is very high. Even if estrogen, vitamine K supplement could not make up the bone loss rate. At present the most study on ASA athlete'bone limited on the ordinary description, which couldn't fully explain the relation with long-time high intensity training induced bone loss and the mechanism on athlete'osteodystrophy. Hence these disturbed the study on prevent and treatment about athlete'osteoporosis. Today we use 2-month female rats carry through training in treadmill for 10 weeks to simulate phenomena of athlete secondary amenorrhea. When we established the model about athletic secondary amenorrhea, we studied the changes of bone in rats with estrous cycle inhibited and discussed the mechanisms of bone in athletic secondary amenorrhea. Our study would offer experiment foundation in order to prevent and therapy atheletes' osteodystrophy and the constitution of children's exercise load. Experiment 1 The foundation of animal model in rats with estrous cycle inhibitedWe used 2-month female rats as our research objective. Rats were devided into three groups: control(n=20), middle intensity training group(n=20), high intensity training group(n=40)(treadmill, 6days/week, lOweeks). During training we study the changes of indexes such as estrous cycle, body weight, Hb, BUN, BLA and so on. After training we assay the capacity of estrogen, progesterone and cortisol in all rats. We found that all indexes were not change in control and middle intensity training group significantly. The estous cycle of rats in high intensity training group were settled in long time. And their body weight were lower than that of control, Hb were reduced gradually, BUN and BLA were elevated fluctuatly. These results indicated high intensity training lead to fatigue, and these fatigue indexes could used to evaluate the foundation of animal model in rats with estous cycle inhibited. After 10 weeks high intensity training , the capacity of estrogen and progesterone were lower than those of control, and the level of cortisol werevery higher than that of control. These results showed us the foundation of rats model were feasibility in our study. The indexes of rats with estrous cycle inhibited were gradually recovered after 20 days at rest. This told us the phenomena about rats with estrous cycle inhibited were reversed after rest. Experiment 2 The changes of bone in rats with estrous cycle inhibitedAt present the data were mostly focus on clinic indexes such as bone metabolism biochemics parameter and bone mineral density. We study the effect of estrous cycle inhited on bone through multi ways. We use microscopes and transmission electron microscopes to observe the structure of femur and vertebra in four groups. Colorimetry was used to measure bone metabolism indexes. Single photon absorb assay was used to measure bone mineral density. 3-point bending test was used to measure biomechanics in femur and tibiae. The microscopes'result show the cortex area was larger , the amount of ob and bone cell were more in middle intensity training group than that in control. The indexes reflecting bone forming were elevated. The bone mineral density were increased. The maxium load and elasticity load were all elevated in middle intensity training group. The microscopes result show cortex wre thinner and oc were increased and the number of girder were fewer in high intensity training group. The transmission electron microscopes result show old bone cell were more and endosarc was swell...
Keywords/Search Tags:Athletic Secondary Amenorrhea, estrous cycle, puberty, female rat, treadmill, bone metabolism, bone mineral density, biomechanics parameter, insulin-like growth factor -1, estrogen receptor, gene expression, reverse transcription
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