| Introduction:Nowadays, osteoporosis has been a familiar disease which is puzzling the old, and more and more attention has being paid to prevent and cure osteoporosis. But in recent years, medication is primary for this condition, and it always brings more side effects. Therefore, a non-invasive and non-drug method for treating osteoporosis is brought forward. In consideration of the fatigue of bone cell's sensitivity to load, we imposed continuous and intermittent high frequency and low amplitude vibration on animal skeleton, so as to provide a theoretical basis for clinical applications.Methods:Sixty 3-month-old healthy male wistar rats were randomly assigned to seven groups, each with 7 rats:BG (based group), SBG (suspended base group), CVG(continuous vibration group),1DVG(1-day-intermittent vibration group, followed by analogy),3DVG,5DVG,7DVG, and 11 rats were standby. Six of the seven groups were trail-suspension except BG. Vibration loading began a week after the operation, and frequency is 35 Hz, the acceleration is 0.3 g,15 min/ day, totaling 8 weeks. In the period of experiment, we measured the weight of all rats once a week. Rats were killed by anaesthesia, and we gave all rats electroneurogram of sciatic nerve the day before killed. We selected the fresh bone for three-point bending test and non-decalcification slice observation.Results and Conclusion:1. Weight of the rats:To prevent the testis from sliding into abdominal cavity when subjected to tail-suspension, we extruded the testis from abdominal cavity in the period of trail-suspension. Although there were huge differences between every rat especially the weight of the rats, a continued weight gain of groups given vibration kept close to or almost same as that of based group hroughout the suspension period. So it may be a useful model for simulating the effects of long-term weightlessness.2. The electroneurogram of sciatic nerve shows:After 8 weeks, the potential conductionvelocity level of the groups given vibration was lower than, and SBG fell nearly 1.16m/s than based group, CVG fell nearly 2.1m/s, and 1DVG,3DVG,5DVG, 7DVG fell about 1.15 m/s,1.8 m/s,1.64 m/s,1.29 m/s. According to the theory of Norris, degressive value of groups given vibration was between 0-3m/s, so the effects of peripheral nerve conduction velocity with 8 weeks was not significantly affected. But if long-term treatment will impact the peripheral nerve and vibration in the clinical treatment also need to be researched.3. Three-points bending test results shows:â‘ The maximum damage load of tibias of SBG was lower than the BG, and there were serious signs of. Groups given vibration were better than SBG, although they were worse than BG. In the vibratory groups, 7DVG was the best,1DVG and 3DVG were a little lower than 7DVG, but CVG and 1DVG were not obvious.â‘¡The ability of SBG to resist deformation was lowermost aniong all the groups, and the osteoporosis was severe. The improvement of other groups was similar with the maximum damage load.â‘¢In the elastic modulus,3DVG was almost the same as CVG, and the effect was poor. The SBG was the worst assuredly.1DVG,7DVG changed greatly, and the effect of 7DVG was the most bvious group. There was also much increase in 5DVG.(?). The results of morphometry:In fluorescence double labeling:From the area and distance between the two fluorescence labeling we can see clearly that the growth rate of trail-suspension group was lower than basic group, and there were almost no normal trabecular bone because of osteoporosis. But vibration given to the rats could promote bone growth and increased bone mineral apposition rate, and intermittent vibration was better than continuous vibration group to stimulate bone growth.7DVG was relatively obvious, followed by 1DVG and 3DVG group, and 5DVG was a bit dissatisfied.Observation of static histomorphometry test:Percentage of trabecular area (%Tb.Ar) of SBG and other groups were lower than BG obviously, but the vibrational groups were better than SBG.7DVG was the best one of all the groups. Trabecular separation (Tb.Sp) of SBG was huge related to osteoporosis. For the group which received vibration, the number of the %Tb.Ar and trabecular thickness (Tb.Th) were enhanced, and the Tb.Sp was decreased. This means that the macrostructure and the microstructure of bone were improved, bur the vibration cycle was very crucial. The results of 7DVG was obviously reformed, followed by 1DVQ 3DVQ 5DVG and CVG.So, for 3-month-old healthy male wistar rats, frequency of 35 Hz and the acceleration of 0.3 g can be a well treatment to osteoporosis of suspended rats. In all intermittent vibration groups,7DVG does the best work.
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