The Osteoporosis Study Of Mice Suspending And Ovariectomized; And The Influence Of Exercise On Mechanical Capability Of Mouse Tibia

Although the biomechanics has been studied for a century, ithas not been formed a mature embranchment up to the present. Itis a difficult thing to introduce mechanical theory into organism,biological tissue and apparatus, because the main characteristicof organism is that it has "life". There is essential differencebetween the structure of zeotic alive tissue and nonlivingengineering material.Osteoporosis is one of the common diseases of astronaut,old persons and women who are in the time of menopause. Thisdisease disturbs people universally. The methods of the mice ofthe tail suspending and ovariectomizing are the two preferableexperiment models of studying osteoporosis in the science atpresent time. This paper mainly studies biochemical index andmechanical capability of tibia of the experimental mice whichhad been suspending and ovariectomizing throughpre-experiments twice and the module variations of theexperimental mice's trabecular bone and cortical bones bystimulating them in the same condition.The first pre-experiment was divided into normal group,suspending group, castrating group and artificial operation group.Each group had 12 experimental mice, and each group killed 3mice at 4th week, 6th week, 8th week and 12th week separately.Each time, sample blood of the mice were tested: blood serumcalcium ion and ALP;eliminating the musculature around thetibia, gluing the strain parcels in the central part of tibias,loading the tibias of the mice though the researched axiallyloading system and tested the cases of fatigue strain of variousgroups of the same load ( 1N );putting the whole tibia in thestator, conducting axially destroying compress in the electronicomnipotence testing machine and testing the broken load of eachgroup.The result of the first pre-experiment were:1. After 4 weeks, blood serum calcium ion was 2 .21%lowerthan the normal group and the content reduced gradually with theweeks;whereas the ALP of the blood was 61 .51%higher than thenormal group and the content reduced rapidly with weeks. After4 weeks, blood serum calcium ion of the ovariectomized micewas 4 .80%higher than the normal group and the content reducedgradually with the weeks;whereas the ALP of the bloodwas 61 .51%higher than the normal group and the content reducedrapidly with weeks.2. The tibia axial variation of the experimental micereduced gradually after putting on the same load ( 1N ) in the tibialoading equipment with weeks and the tibia axial variation ofsuspending group and castrating group was higher than thecontemporary normal group. After 4 weeks, the tibia axialvariation of suspending group was 27 .31% higher than the normalgroup;the tibia axial variation of the castrating groupwas 62 .44%higher than the normal group and the artificialoperation group. After 12 weeks, the tibia axial variation ofsuspending group was 17 .75%higher than the normal group;thetibia axial variation of the castrating group was 53 .74%higher thanthe normal group and 92 .92% higher than the artificial operationgroup.3. After 4 weeks, the ability of axially compress destroyingof the mice of the tail suspending and ovariectomized micedecreased, and it represented as the decrease of the biggesttension and the biggest tension of suspending group was7 .00%lower than the normal group in the contemporary time, andthe biggest tension of the castrating group was 11 .72%lower thanthe normal group that of the normal group. Moreover, during thetime of 4 weeks and 6 weeks, the ability of axially compressdestroying of the mice of the tail suspending and ovariectomizedmice decreased rapidly. The load of axially compress destroyingof the mice of the tail suspending in 6 weeks and 12 weeks was16 .35%and 16 .35%that in 4 weeks;the load of axially compressdestroying of the castrating group in 6 weeks and 12 weeks was11 .88%and 10 .59% that of in 4 weeks.The second pre-experiment was divided into normal group,suspending group, suspending load group, castrating group andcastrating load group and each group had 5 mice;when the miceof load were raised, they did dynamic vivi-movement withoutdamnification for 15 minutes everyday and their load andfrequency were 3 Nand 5 Hz. After 4 weeks, they were all killed.Using minitype increasing-force machine to test the elasticmodule of trabecular bones near the tibias and using theelectronic omnipotence testing machine to test the elastic moduleof cortical bones of the central part of tibias.The result of the second experiment were: after 4 weeks ofsuspending their tails, the elastic module of trabecular boneswas 21 .39%that of normal group, the elastic module of the corticalbines was 90 .06%that of normal group;whereas the elastic moduleof trabecular bones of the mice which were given movementwas 75 .94%that of normal group, the elastic module of corticalbones of the mice which were given movement was 99 .32%that ofnormal group. After 4 weeks of castrating, the elastic module oftrabecular bones was 37 .43%that of normal group, the elasticmodule of the cortical bines was 76 .81%that of normal group;whereas the elastic module of trabecular bones of the mice whichwere given movement was 77 .49%that of normal group, the elasticmodule of cortical bones of the mice which were given movementwas 79 .01%that of normal group.We can draw the following conclusions from these twoexperiments:1. A better model of osteoporosis can be gotten from theexperiment of tail suspending of mice and ovariectomized miceafter 4 weeks. It has an obvious reducing tendency in the aspectsof biochemical index and mechanics than that of normal group.2. The osteoporosis of the experiments of the mice of thetail suspending and ovariectomized mice becomes more obviouswith the weeks.3. After movement-stimulating, it can slower the loss of thecontent of bones of experimental mice and this can be benefit forkeeping the content of bones and can maintain a betterbiomechanical capability.4. From the aspect of mechanics, these experimentscalculate the elastic module of trabecular bones and corticalbones of experimental mice objectively and the result providesthe future scientific experiment with reference value.