| Introduction: In recent years, much attention was paid to vibration for preventing and the treatment of osteoporosis in the old. In consideration of the fatigue of bone cell's sensitivity to load, we put forward a method in combination of continuous and intermittent vibration, by seeking the most appropriate treatment period through animal experiments, so as to provide a theoretical basis for clinical osteoporosis.Methods: 6-month-old healthy female wistar rats were divided into 6 groups randomly (12/every group): 1DVG(1-day-intermittent vibration group, followed by analogy), 3DVG, 5DVG, 7DVG, CVG(continuous vibration group), OCG (ovary control group). All the rats were removed ovary. The vibration began a week after the operation, then all rats were sacrificed by heart pumping after 8 weeks and 12 weeks. We selected the fresh bone.Results: (A) The electroneurogram of sciatic nerve shows that: According to compare the potential conductionvelocity after 8 weeks, we saw that all the other groups did not change except the OCG, and the CVG is the lowest, and it fall nearly 10.49% than the CVG.1DVG fall 1.92%; 1DVG, 3DVG, 5DVG increased slightly, followed by 0.58%, 2.90% and 4.25%.The data that was obtained after 12 weeks showed that: potential conductionvelocity of the OCG was the highest, and potential conductionvelocity of other groups declined in different degrees.3DVG group was the same as the CVG; 1DVG had a smaller decrease about 3.05%; CVG,5DVG,7DVG were significantly lower than the OCG followed by a decrease of more than 9.9%,8.9%,9.0%. (B) Three-points bending test results showed: the maximum damage load, elastic modulus and damage deflection of the OCG were all lower than those of other groups. There were obvious signs of osteoporosis, and its ability to resist damage was significantly lower than other groups. The maximum damage load: 7DVG was the best group, and its maximum damage load increased nearly 33.57%. 5DVG was lower. It increased 32.65%.CVG, 1DVG,3DVG also improved , which increase 30.03%, 22.24% and 22.56%; The ability of 3DVG to resist deformation increased 40.68% than CVG, 7DVG increased 32.77%, CVG increased 27.12%,5DVG increased 15.25%, 1DVG changed little, and it only increased 2.26 %; in the elastic modulus, 1DVG was almost the same as 3DVG, the effect was poor. 5DVG, 7DVG changed greatly, they increased by 16.04%, 50.77% and 40.44%. The effect of 7DVG was the most obvious group.The data from 12-week showed: After 12 weeks of vibration, except the 7DVG, the maximum damage loadand the damage deflection of all the other groups were not significantly increased. To the opposite some indicators even decreased. However, elastic modulus of all the groups has a significant increase except the 1DVG. The elastic modulus of 7DVG was greater than other groups obviously, and it increased nearly 30.39 %.The followings were 3DVG,5DVG,CVG.(C) Observing the results of morphometry: In fluorescence double labeling: after 8 weeks, we can see clearly that the growth rate of intermittent group was higher than basic group, in which the most obvious group was the 7DVG. In the OCG showed the phenomenon of retardation, and majority of trabecular bone was in the stationary phase; After 12 weeks, the vibration groups were better, and interlabel width was more apparent. The state of The OCG was bad. But we can see the growth of bone. Although the double distance of OCG was greater than 5DVG and CVG, and it is the same as the 1DVG and 7DVG. But its rate-mark was much lower than vibration group. The growth of 3DVG was the best.Comparison of morphometric data showed: As the trabecular separation of 8-week group was concerned, OCG was much higher than vibration group, and in the thickness and area of trabecular bone was significantly lower than the vibration group. From the comparison of Vibration group, we can see: the trabecular separation of 7DVG was the smallest. The 1DVG and 5DVG was almost the same as the 7DVG. There was little difference between CVG and 3DVG. The results of Trabecular thickness were similar to the result of trabecular separation. But the percentage of trabecular bone on the area, 5DVG showed the largest percentage of value, followed 7DVG,3DVG, 1DVG and CVG.The groups of 12 weeks showed that except the 7DVG and CVG, the other vibration groups were similar to the OCG. The trabecular thickness and percentage of area of 1DVG and 3DVG were less than the OCG. Compared the 7DVG and CVG, and its indicators were better than that group.Conclusion and discussion: As mentioned above we can see:(A) from the effects of vibration in the treatment of osteoporosis on the peripheral nervous system we can see: The effects of peripheral nerve conduction velocity with a short-term vibration (8 weeks) was not significantly affected. But long-term treatment (12 weeks) will impact the peripheral nerve. The long-term sustained vibration had been able to moderate peripheral neuropathy which causes the delay.That was not allowed in the clinical treatment.(B) Mechanical properties: from the 8-week group we can clearly see that the effects of the vibration on the early osteoporosis treatment. The mechanical properties of vibration group were better than OCG. The greatest damage in the load of 1DVG was similar than 3DVG, and the 5DVG was similar than 7DVG and CVG. The maximum damage load of 7DVG increasedthe most obviously; In the destruction of deflection, 3DVG was higher than other groups (reasons unknown). The result of other groups was similar as the result of maximum damage load;Data 12-week, we increased the number of samples, expect more statistical data. After an increasing of the four weeks, we found: the effects of 1DVG and 3DVG on the treatment of osteoporosis was not obviously. 7DVG was almost the same as the OCG. The vibration in this cycle is nonsense we can see changes only in 7DVG. The damage deflection of all the group did not changed obviously, except the 7DVG; However, compared the vibration group with the OCG, we still can see the meaning that the resistance to fracture caused by d osteoporosis.(C) Observed on morphometry: a qualitative analysis from the picture we can basically determine the vibration can restrict the destruction and dissolution of bone. The effect of 8 weeks morphometry is more obvious. OCG showed a trend of osteoporosis in trabecular separation degrees, the thickness of trabecular bone area or the percentage of trabecular bone. The vibration will be able to restrict this trend. This shows that the vibration can effectively prevent and treat osteoporosis in the early menopause. In addition, intermittent vibration is superior to continuous vibration group. 7DVG is the best.12-week results of morphometric showed that: in the medium and long-term treatment, the vibration was still able to prevent and treat osteoporosis. But its effect was related to the cycle of the vibtation. In the long-term Vibration, 1DVG, 3DVG do not had basic meaning for the prevention and treatment; Time of the CVG may cause fatigue and bone cells lead to "overkill". That would result the extensive of trabecular bone, as the off-chip; 5DVG and 7DVG could be considered for clinical prevention and treatment, in which 7DVG was the best.Generaly considered the observation of electroneurogram, mechanical properties and morphometry of rats, we can see that the vibration in the treatment of osteoporosis had significance, and the effect of prevention and treatment of its early stage in post-menopausal osteoporosis was obvious. In the medium and long-term, 1DVG and 3DVG was not applicable to the treatment.5DVG and 7DVG were applicable. But their efficacy on long-term effect and the side effects such as peripheral nerve had not been researched yet. |
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