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Objective To investigate the effects of different interventions on the biomechanic indexes in femur bones of ovariectomized rats with osteoporosis.Methods Eighty healthy female Sprague-Dawley rats,aged 3 months,were randomly divided into an ovariectornized(OVX,n=68)group and a sham-operation(Sham,n=12)group.At the 11th week after the operation,the OVX group was further randomly divided into a control group(n=11),an estradiol group(E2,n=10),a genisteine group(G,n=10),a treadmill exercise group(TE,n=10),a lithium chloride group(LiCl,n=10)and a whole-body vertical vibration group (WBVV,n=10).Then the rats began to receive different interventions as their group names implied.At the end of 8 weeks,their right femurs were isolated and the biomechanic parameters were detected using the three point bending test.Results (1)Both the maximum load and elastic load in E2,G,TE,WBVV and LiC1 groups were significantly higher than that of the control group,while no significant differences were seen in maximum deflection and elastic deflection.(2)The elastic stress,maximum strain,and elasticity modulus in E2,G,and WBVV groups were significantly higher than that of the control group,while no significant differences were seen in maximum stress and elastic strain among them.The maximum stress,elastic stress,maximum strain,and elasticity modulus in TE group were significantly higher than the control group while no significant differences were seen in the elastic strain.The maximum stress,elastic stress,and elasticity modulus in LiC1 group were significantly higher than the control group,but no significant differences were seen in maximum strain and elastic strain between them.Conclusion E2,genistein,treadmill exercise,whole-body vertical vibration,and LiC1 have quite similar effects on structural mechanics indexes of femurs in OVX rats with osteoporosis,but they have different impacts on the material mechanics indexes.
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BACKGROUND:Osteoporosis is a bone metabolic disease that affects women more than men. Prevention and treatment of osteoporosis is becoming a serious medical problem because of the aging of the population. OBJECTIVE:To explore the effects of lithium chloride treatment on bone microarchitecture and bone marrow stromal cel differentiation of ovariectomized osteoporosis rats. METHODS:After ovariectomy, 28 of 30 healthy female Sprague-Dawley rats, 3 months old, were randomly divided into the folowing three groups: ovariectomizedin vivo group (9 rats), ovariectomizedin vitro group (10 rats), and lithium chloride group (9 rats). At the 11th week postoperatively, rats in the lithium chloride were intragastricaly injected with lithium chloride at a dose of 15 mg/kg, three times per week. After 8 weeks of treatment, the bone microarchitectures of the rat left femur in the ovariectomizedin vivo group and lithium chloride group were detected by micro-CT. The bone marrow mesenchymal stem cels were freshly isolated from the bone marrow of the bilateral femurs and tibia of rats in the ovariectomizedin vitro group. After 24 hours of inoculation, the cels were cultured in lithium chloride and divided into 0 mmol/L (control), 1 mmol/L and 5 mmol/L groups. At 6 and 8 days of culture, the medium was changed and lithium chloride with the corresponding concentrations was added. At 10 days of culture, western blot assay was adopted to detect protein expression of Runx-2, SP7 and PPARγ2. RESULTS AND CONCLUSION:(1) Compared with the ovariectomizedin vivo group, the volume density of trabecular bone, number of trabecular bone, and bone volume fraction in the lithium chloride group were significantly increased and the separation of trabecular bone was significantly decreased. However, no differences were seen in the thickness of trabecular bone and structure model index. (2) Lithium chloride at 1 and 5 mmol/L could increase the protein expression of Sp7 and Runx-2 in bone marrow stromal cels, but decrease the protein expression ofPPARγ2. These results indicate that lithium chloride may improve the microarchitecture of the trabeculr bone in ovariectomized osteoporosis rats through stimulating the osteogenic differentiation of bone marrow stromal cels.
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BACKGROUND:FoxO1 participates in diverse processes of cellphysiology, including cellproliferation and apoptosis, reactive oxygen species, longevity, cancer, the regulation of cellcycle and metabolism. Vibration loading is believed to promote metabolism, delay muscle fatigue, and facilitate adaptive bone reconstruction. OBJECTIVE:To investigate the effects of whole-body vertical vibration on the protein expression of FoxO1 in tibia and bone marrow cellof ovariectomized (OVX) osteoporosis rats. METHODS:Thirty-six healthy 3-month-old female Sprague-Dawley rats were randomly divided into the fol owing three groups by body weight:sham-operation (sham) group, OVX group, and OVX whole-body vertical vibration (OVX+V) group. At the 11th week after operation, the OVX+V group rats were vibrated on a vibration platform twice per day for 7 weeks according to the fol owing schedule:whole-body vertical vibration for 15 minutes, with an interval of 10 minutes. The frequency was 90 Hz and the amplitude was 0.5 mm. Within 24-48 hours after the last treatment, the fifth lumbar vertebra as wel as the right femur and tibia were isolated. The bone mineral density of the fifth lumbar vertebra and right femur was detected by dual-energyΧ-ray absorptiometry. The FoxO1 protein expression in proximal tibia and bone marrow cells was detected by western blot assay. RESULTS AND CONCLUSION:As revealed by the results of bone mineral density, the bone mineral densities of the proximal and distal femur as wel as the fifth lumbar vertebra in OVX+V group were significantly increased while no significant difference could be seen in the mid shaft. As revealed by the results of western blot, there was no FoxO1 protein expression in the tibia, but it could be detected in the bone marrow cells. Compared with the sham group, there was no significant difference in FoxO1 protein expression in bone marrow cells of OVX group;compared with the OVX group, the protein expression level of FoxO1 in bone marrow cells of the OVX+V group was significantly reduced. The results suggested that whole-body vertical vibration could inhibit the protein expression of FoxO1 in bone marrow cells of osteoporosis rats.
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Objective The aim of this study was to observe the effects of whole-body vertical vibration, treadmill exercise, genistein administration and estrogen injection on the uterus weight index and uterus histology as well as the ex-pression of glycogen synthase kinase ( GSK-3β) protein in the uterus of ovariectomized osteoporotic rats.Methods Sev-enty-two healthy 3-month old female SD rats were randomly divided into two groups by body weight:sham-operation group (Sham) and ovariectomized group (OVX).At 10 weeks after OVX operation, the OVX rats were randomly divided into the following five groups by body weight: OVX group, whole-body vertical vibration group (WBVV), treadmill exercise group ( TX) , genistein group ( G) and 17β-estrogen group ( E2 ) .Then they were treated with different methods according to the experiment design.At the end of experiment, the uterus weight was measured with an electronic balance.The uterus histology was observed with HE staining and the expressions of GSK-3βand P-GSK-3βproteins were detected by Western blot.Results Apart from E2 treatment, all the other three treatments did not increase the uterus weight and the thickness of endometrium compared with that in the OVX rats.Apart from genistein treatment, all the other three treatments increased the ratio of protein expression of P-GSK-3βto GSK-3βcompared with that in the OVX rats.Conclusions Both whole-body vertical vibration and treadmill exercise can stimulate the phosphorylation of GSK-3βin the uterus of OVX osteoporotic rats.However, genistein has no such stimulation effect.
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Objective The aim of this study was to observe the dynamic changes of serum and bone marrow levels of alkaline phosphatase ( ALP) in ovariectomized ( OVX) rats.Methods Eighty 3-month-old non-pregnant female Spra-gue Dawley rats were randomly divided into following groups by body weight:baseline group, sham-operation (Sham), and ovariectomized (OVX) rat groups.The rats were killed at 0, 3, 6, 12 or 24 weeks after operation.The changes of serum and bone marrow alkaline phosphatase ( ALP) levels were detected with photometer-721 and the number of ALP-positive bone marrow cells was detected with a research grade upright fluorescence microscope .Results In the sham group, the serum ALP levels were significantly increased in the weeks 3 until the week 6.However, the serum ALP levels were signifi-cantly decreased in the week 12 until the week 24.The ALP-positive cell number in the bone marrow was significantly in-creased in the week 3 until week 12, but significantly decreased in the week 24.In the OVX group, the serum ALP levels were significantly increased in the week 3, but significantly decreased in the week 6 until the week 24.The number of ALP-positive bone marrow cells was significantly decreased in the week 3 until the week 24.In addition, the serum ALP levels in the OVX group were significantly higher than that of the sham group .However, the number of ALP-positive bone marrow cells was significantly lower than that of the sham group .Conclusions The change tendency of serum ALP in the sham group is similar with that of bone marrow cells .But the change tendency of serum ALP in OVX rats is different from that of bone marrow cells .
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Aim To observe the effects of 17?-estradiol(E2)and exercise on the protein expression of peroxisome proliferators activated receptor ?(PPAR?)in bone tissues and bone marrow adipocytes in ovariectomized rats.Methods Forty female Sprague-Dawley rats,aged three months,were randomly divided into the following four groups:sham-operation(Sham),ovariectomized(OVX),ovariectomized plus moderate-intensity treadmill exercise(EX,18 m?minute-1,45 min?day-1,5 uphill,4 times?week-1)and ovariectomized treated with E2(25 ?g?kg-1,3 times?week-1)group.At the end of experiment,the morphological changes of femur and tibia were observed decalcifiedly by HE staining and the protein expression of bone PPAR? was detected by Western blot.Results The number of fat vacuoles and PPAR? protein expression in OVX group was significantly higher than that of other three groups.Conclusion E2 and exercise can benefit the bone morphological structure and these effects might be partly related to the inhibition of both PPAR? protein expression in bone tissues and adipogenic differentiation of bone marrow in OVX rats.