Study of the influence of vibration oscillations of different frequency, amplitude and vibration acceleration on the structural and functional state and mechanisms of muscle tissue remodelling. An experimental study was conducted on sexually mature male rats. The rats of the four experimental groups were subjected to vertical vibration oscillations of 15, 25, 50 and 75 Hz, respectively. It has been established that pathological changes in muscle tissue in the form of different variants of damage and remodelling tend to increase, which correlates with the frequency of vibration, amplitude and vibration acceleration level, as in the 2nd group, where the maximum permissible vibration levels did not exceed the established allowable norms, and in other groups of animals, where the permissible levels of total vibration were exceeded. By increasing vibration acceleration for more than 1.25 m/s2 (0.13 g, frequency more than 25 Hz and amplitude of 2 mm), severe damages are observed in the form of alterative changes of muscle fibres with the disappearance of transverse strain, homogenization of sarcoplasm, fragmentation with dissociation fibres on separate beams, partial and subtotal myocytolysis, and necrosis of separate fibres. Inflammation is rapidly increasing with the increase in the frequency of vibration and the level of vibration acceleration for more than 5.0 m/s2 (0.51 g).
Objectives Osteoporosis often occurs in individuals of different age groups, frequently during menopause and after ovariectomy. It increases the risk of pathological fractures almost twice. The aim of our research was to assess bone metabolism, nanocomposite structure of the tibia under conditions of ovariectomy and zoledronic acid treatment. Methods X-ray diffraction has been performed for nanostructure analysis of mineral crystallites and crystal lattice of hydroxyapatite in the tibia samples of ovariectomized rats with additional application of bisphosphonate zoledronic acid (0.025 mg/kg). Markers of remodeling – osteocalcin, alkaline phosphatase, tartrate resistant acid phosphatase 5b – were determined. Quantitative amount of calcium in the bones was detected by atomic absorption method. Results Zoledronic acid prevented loss of mineral mass after ovariectomy. Rats after ovariectomy, treated with zoledronic acid, showed statistically higher (р<0.05) values of crystalline phase and calcium content compared with the SHAM-surgery and ovariectomy groups (р<0.05). Zoledronic acid inhibited bone remodeling, which is proved by tartrate resistant acid phosphatase 5b reduction and inhibition of osteoclasts during the experiment. Conclusions These results enable to suggest that zoledronic acid can improve mineral mass of the bone during menopause in individuals of different age groups.
Objective. Clinical use of glucocorticoids is a frequent cause of secondary osteoporosis, which reduces the mineral density of bones and results in pathological fractures. Mechanical stimulation as non-physiological high-frequency vibration with low acceleration prevents the loss of a crystalline component and stimulates the anabolic remodeling of the bone. The aim of the present research was to assess the impact of mechanical vibration on the bone structure in rats, which received glucocorticoids. Methods. Wistar rats were randomized into three groups: Vehicle control (Veh), Methylprednisolone sodium succinate (Mps), and Mps combined with whole-body vibration (WBV). Rats of Mps+WBV and Mps groups received 3 mg/kg/day of methylprednisolone every other day for 24 weeks and rats of Veh group received 0.9% saline (sodium chloride). The group of rats Mps+WBV was subjected to WBV for 30 minutes per day for five days a week with parameters 0.3 g and frequency 50 Hz. Relative amount of crystalline component and collagen in the bones was determined by X-ray diffraction (XRD) and calcium level – by atomic absorption spectroscopy. Bone tissue metabolism was assessed by determining the concentration of markers, in particular osteocalcin and Tartrate-resistant acid phosphatase (TRAP5b). Results. Glucocorticoids induced a considerable increase in the rats body mass (+13%) and decreased the content of mineral component in the femoral neck (–17%) in Mps group compared with Veh. The process of the bone metabolism was significantly accelerated, which is proven by an increased level of remodeling markers. It should be mentioned that WBV did not allow significant decrease in mineral component of the bone to 16th week of the experiment compared with Mps group, although these parameters did not achieve the indices in the Vehicle control group (–10%). Our investigation allows to suggest that mechanical high-frequency vibration of low intensity can partially inhibit the harmful consequences of glucocorticoids on bone structure in rats. Despite the positive impact of vibration on the bone tissue after Mps introduction in the 8th–16th week, this influence was not statistically reliable in the 24th week of the experiment. Conclusions. The results of our investigation on animal model indicate that non-physiological vertical mechanical vibrations are an effective means to prevent loss of a mineral bone component during treatment with glucocorticoids.
The aim of the study was to evaluate the effect of nonphysiological whole body vibration (0,3g) on the bone structure and metabolism in rats treated with methylprednisolone (3 mg/ kg/day every other day, 24 weeks). Amount of crystalline component and collagen in the bones was determined by X-ray diffraction method, and the level of calcium by atomic adsorption spectroscopy. Bone metabolism was assessed by determining the concentration of markers - osteocalcinandtartrate-resistant acid phosphatase 5b. Methylprednisolone reduced the content of the mineral component in the tibia (–16.8%) in I group compared with the control. This significantly accelerated the process of bone metabolism, as evidenced by the increased level of bone remodeling markers. It should be noted that the total nonphysiological whole body vibration did not allow a decrease in the mineral component of the bone until 16 weeks of the experiment compared with I group, although these values were lower than the control group (–28.3%). We suggests that mechanical high-frequency low-intensity whole body vibration can inhibit the negative effects of glucocorticoids on bone structure.
This study aimed to investigate the influence of high-frequency whole body vibration (WBV) on metabolic and structural responses of rats' bone tissue under the sedentary lifestyle and obesity. Obesity combined with a sedentary lifestyle can present the potential negative health effects. However, whole body vibration can be used as a means of non-pharmacological correction of bone mineral density. For characterization of bone nanocomposites organisation and prevention of mineral density loss, X-ray diffraction method was used. Markers of bone remodeling in the rats' blood: leptin, osteocalcin, tartarate resistant acid phosphatase 5b, alkaline phosphatase. Using a high-calorie diet and low-mobility model, we proved that bone mineral mass had been decreasing since 8th week. It should be noted that the decrease in the relative amount of crystalline phase (hydroxyapatite) continued throughout the experiment, up to 24 weeks (p<0.05). These structural changes were accompanied by changes in quantitative indicators of the bone remodeling markers. Rats had lower bone mineral density compared to the animals that were on the normal diet and were additionaly affected by WBV. We observed the increase of the crystalline phase volume fraction from 84% to 93% (p<0.05) in group with additional whole body vibration and the decrease of the mineral component in rats with limited mobility and high-calorie diet. Therefore, WBV could improve structural conditions of bone and prevent fat accumulation and obesity-associated biochemical markers in obese rats. This can be an effective method to improve the structural and functional state of the bones while preventing the loss of bone mineral density.
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