| purpose By on the experiment made in rabbit targeted necrosis of the femoral head of rabbit model of hormone-based study using a large number of glucocorticoid induced hypercoagulability state thrombophilia causes and lead to avascular necrosis ofemoral head pathophysiological mechanisms,as well as steroid-induced femoral head necrosis and blood rheology changes in the relationship between the hormone in order to further explore the pathogenesis of osteonecrosis.At the same time,the rabbit femoral head for avascular necrosis of the pathophysiological changes observed lipid-lowering drugs on hormone-type role in the prevention of osteonecrosis of the femoral head.Methods healthy adult New Zealand white rabbits were 46,male and female open, body weight(3.0±0.3) kg,were randomly divided into 3 groups.A group(control group),10:intramuscular injection of normal saline every day;B group(model group), 18:by ear vein injection of 10μg / kg LPS(E.coli endotoxin),24h after the hip muscular injection of 20mg/kg MPS sodium succinate(methylprednisolone),a total of 3 times,each time interval 24 h,non-oral pravastatin sodium;C group(treatment group),18:Methyl strong Song Long + E.coli endotoxin + oral pravastatin sodium 2.5mg/kg.4,6,8,10,12 in the first week after administration line serum cholesterol, triglycerides,blood rheology,coagulation function tests,and the application of statistical software version SPSS10.0 of data between the two groups using t test compared to P＜0.05 as a statistically significant difference with the standard analysis of the data.Executed in the first week of 6,8,10,12 rabbits with bilateral femoral head line from the whole specimens,histopathological sections of conventional light microscopy,electron microscopy examination and vascular endothelial growth factor (VGEF) Immunohistochemical staining of microvascular thrombosis of the femoral head(MSB) staining,according to diffusion in the air or bone lacuna bone karyopyknosis whether the cells around the bone tissue necrosis of femoral head avascular necrosis as a histopathologic feature of the criteria for each group of animals the rate of femoral head necrosis statistics.Rabbit in the 12-week double-line hip X-chip,MRI examination.results The group B in serum triglycerides at 10 weeks in the(6.87±0.33mmol/l) was significantly higher than A group(1.21±0.38mmol/l),there was a significant difference(P＜0.05),8 weeks,group B cholesterol content(6.57±0.33mmo/l) higher than the A group(1.96±0.33mmol/l),there was a significant difference(P＜0.05),12 weeks of group B plasma viscosity and low shear rate whole blood viscosity,respectively(4.29±0.34mpa.s),(6.35±0.75mpa.s) than A group(1.28±0.25mpa.s),(2.69±0.36mpa.s) significantly increased,significant differences(P＜0.05).C group at 12 weeks of cholesterol,triglyceride content,respectively(2.89±0.29mmol/l),(2.32±0.58mmol/l) was significantly lower than B group(6.84±0.32mmol/l),(5.35±0.25mmol/l),with significant difference(P＜0.05),C group at 12 weeks plasma viscosity and low shear rate whole blood viscosity,respectively (1.96±0.17mpa.s),(3.15±0.35mpa.s) significantly low - in the B group(4.29±0.34mpa.s),(6.55±0.65mpa.s),significant differences(P＜0.05).C group than in A group,8 weeks,when the indicators are significantly different(P＜0.05),over the period was no significant difference(P＞0.05).Group B in the four weeks after the model of prothrombin time(PT) than the A group extension of eight weeks at(5.32±0.33) than the A group(9.13±0.48) was significantly longer,P value＜0.05,significant difference,6 week activated partial thromboplastin time(APTT) began to be shortened to 10 weeks for(17.62±0.48) than the A group(35.68±0.22) significantly shortened,P＜0.05,significant difference;C Group 6 after administration shortened week,but when the eight weeks to return to normal,10 weeks at(7.23±0.28) than the B group(5.16±0.27) a significant difference,P＜0.05,C 8-week group than the A shortened APTT,but 10 week close to the normal level,12 weeks for(27.59±0.17) than the B group(16.37±0.25) with significant differences.Histopathology showed that Group B at six weeks of the femoral head and neck around the cancellous bone and cartilage area of necrosis,trabecular bone begins to shrink,and become thin,bone nuclear margination,condensation,8 weeks the number of spatial and temporal bone lacuna percentage of 59 percent,the number of osteoblasts decreased significantly,10 of bone marrow cells obviously fat,marrow was to occupy a large number of fat cells,12 weeks microthrombus staining showed a large number of thrombosis,luminal stenosis or atresia embolism,vascular wall thickening bone,tissue VEGF expression was significantly reduced the incidence of osteonecrosis of the femoral head was 64%.Pathology and B Group C Group over the same period,the area of osteonecrosis of the femoral head with a significant decrease in trabecular bone density increased in the femoral head marrow significantly reduced the number of fat cells,bone lacuna space ratio of 13.9%,VEGF expression within the bone tissue significantly increased the incidence of osteonecrosis of the femoral head was 23%.Model group B after 6 weeks,X ray showed bone of the femoral head appears fuzzy, irregular translucent areas;the first 12 weeks,with varying degrees of cartilage surface collapse,translucent zone formation around sclerosis,joint space narrowing, C Group when the first six weeks with mild osteoporosis,trabecular bone is slightly vague,unclear head low profile,no obvious cystic change and hardening zone in the first 12 weeks was not found in cartilage and joint space narrowing collapse.MRI showed that Group B at 12 weeks to point T1 of the femoral head,thread-like,patchy low signal,C group no significant change.Conclusion(1) through a single low dose of LPS(E.coli endotoxin) and repeated high-dose MPS(MP) model,the rabbit-type hormone incidence of avascular necrosis of femoral head is 88.7%,as a types of safe and effective production of hormone-based model of osteonecrosis of the femoral head.(2) the application of hormone and model of E.coli endotoxin,the resulting dyslipidemia,serum cholesterol,triglyceride content increased,while the formation of hyperlipidemia fatty degeneration of bone marrow cells,leading to slow blood flow, stasis,whole blood viscosity,plasma viscosity and erythrocyte aggregation index increased,micro-thrombosis and hence the occurrence of avascular necrosis of femoral head there is a close relationship,coagulation dysfunction,prothrombin time, activated partial prothrombin time,blood was hypercoagulable state,microcirculation, and promote micro-thrombosis and progress to increase the incidence of avascular necrosis of femoral head.(3) the use of pravastatin,the effective in improving lipid metabolism,regulating blood coagulation to prevent high blood hypercoagulability state of easy bolt the occurrence of hormone-type head lower the incidence of avascular necrosis.
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