| Objective:1.To verify the feasibility of rapid establishment of rabbit osteoporosis model by ovariectomy(OVX)combined with intramuscular injection of dexamethasone.2.To observe the relationship between bone mineral density and pathology with Length of disease in the osteoporotic fracture of rabbit vertebral osteoporotic fracture.Methods:The experiment was divided into two parts,first part:establish and assessment osteoporosis model;second part:establish and assessment osteoporotic fracture model based on the established osteoporosis model.In the first part,six 6-7 months old female New Zealand rabbits were selected.All the experimental rabbits were treated with castration combined with corticosteroid method to establish osteoporosis model.Before and after modeling,the BMD of L3-L5 was measured by DEXA.The histopathological observation of trabecular bone was performed by histopathological section HE staining.Part 2:Selection of 24 5-7 months old female New Zealand white rabbits were randomly divided into four groups:group A(control group),group B(acute fracture group),group C(subacute fracture group),group D(old fracture group),sex per group.All experimental rabbits were treated with OVX combined with intramuscular injection of dexamethasone method to establish osteoporosis model quickly.The BMD of L3-L5 was measured by DEXA after modeling.After the evaluation of the osteoporosis model,the rabbits were treated with L3 vertebral fractures,and group A was underwent sham operation.The BMD of the vertebral body was measured respectively at the first week,the first week,the fifth week and the ninth week after fracture,and the histopathological observation of the trabecular bone was observed by histopathological section HE staining.Castration and vertebral fractures were performed by the same group of doctors.The data were analyzed by means of SPSS 19.0 statistical software.The data were expressed as X ± s(mean±standard deviation).The t test was used before and after the control.The variance analysis and SNK-q test were used to compare the multiple groups.0.05 was statistically significant.Results:The first part:the average lumbar BMD of the first 6 rabbits in OVX was 284.1 ± 23.53 mg/cm2.The mean BMD of lumbar vertebrae was 191.2 ± 26.65 mg/cm2 in 6 rabbits after OVX,and the trabecurosis of the cancellous bone was significantly thinner and sparse,and the trabecular bone defect The In the second part,the BMD of group A was 165.8±25.10 mg/cm2,the BMD of group B was 163.3 ± 17.75 mg/cm2,and the BMD of the vertebral body in group C was 199.0 ±20.06 mg/cm2,and the BMD of the vertebral body in group D was 227.3.0±30.08 mg/cm2.There was no significant difference between group A and group B(P>0.05).There was significant difference between the other groups(P<0.05).Pathological section HE staining showed that the osteotomy of the cancellous bone of the vertebral body in the D group was disorderly distributed,and there were local trabecular bone fracture and accumulation of a large number of inflammatory cells.Conclusion:1.By ovariectomy combined with intramuscular injection of dexamethasone method,osteoporosis animal model can be established within 3 months.2.Osteoporosis lesions are mainly degeneration of trabecular bone ultrasonography,old vertebral fracture lesions are mainly callus repair with inflammatory cell proliferation.3.The BMD of osteoporotic vertebral fractures increased with the prolongation of the disease.4.The increased bone mineral density of the old bone was consistent with the clinical phenomenon,which provided a reliable basis for clinical research. |
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