| Objective: In this study, measuring the changes of proteoglycan content in nucleus pulposus,pathology and magnetic resonance imaging on rabbit L5-6 by establishing animal model, to simulate weightlessness and +Gz environments to research the long-term effect of simulated weightlessness and +Gz environment on rabbit lumbar intervertebral disc degeneration, and to explore the mechanisms of rabbits’ lumbar intervertebral disc degeneration under the conditions of simulated weightlessness and +Gz. To provide a theoretical basis of preventing the pilots’ lumbar intervertebral disc degeneration. Methods: 1. 40 New Zealand white rabbits were randomly divided into 4 groups of simulated weightlessness repeated exposure group, simulated +Gz repeated exposure group,simulated weightlessness and +Gz repeated exposure group and control group. each group had 10 rabbits which fed 180 days under the same conditions, each group were exposed to the corresponding research condition. 2. Over180 days, all rabbits underwent MRI examination and graded by Pfirrmann standards, results used rank test to compare differences between the groups, P <0.05 was considered to have statistical significant. 3. All rabbits were sacrificed by air embolism in ear vein, Phloroglucinol spectrophotometry method was used to measure proteoglycan content of rabbits’ L5-6 nucleus pulposus, convered according to the standard curve of proteoglycan, and calculated the proteoglycan content. Statistical difference between the groups were compared by variance analysis, P <0.05 was considered to have statistical significant.4. Cut all rabbits’ L5-6 intervertebral disc and then did the HE staining. The results graded by Nishimura standards, and used rank test to compare statistical difference between the groups, P <0.05 was considered to have statistical significant. Result: 1.MRI: Control group: Pfirrmann graded as Class II~III,80% of the rabbits’ no significant interverterbral disc degeneration,high signal on T2 WI,nucleus pulposus and annulus boundaries clear;Simulated weightlessness repeated exposure groups: Pfirrmann graded as Class II~IV,80% of the rabbits’ disc signal slight decreased on T2 WI, nucleus pulposus and annulus boundaries not clear and so on interverterbral disc degeneration performance; Simulated +Gz repeated exposure group:Pfirrmann graded as Class II~IV, 70% of the rabbits’ disc signal moderate decreased on T2 WI, nucleus pulposus and annulus boundaries not clear and so on interverterbral disc degeneration performance;Simulated weightlessness and +Gz repeated exposure group: Pfirrmann graded as Class III~V, 80% of the rabbits’ disc low signal on T2 WI, nucleus pulposus and annulus boundaries disappear and so on interverterbral disc degeneration performance.each group degeneration differences were statistically significant(P <0.05).2. Proteoglycan: Control group: 10.61±1.60mg/ml; Simulated weightlessness repeated exposure groups: 6.52±0.27mg/ml; Simulated +Gz repeated exposure group: 5.31±0.47mg/ml;Simulated weightlessness and +Gz repeated exposure group: 1.51±0.29mg/ml, each group differences were statistically significant(P <0.05). 3.Pathology: Control group: Nishimura graded as Class1~2,80% of the rabbits’ no significant interverterbral disc degeneration,missing part of the nucleus puposus,the inner annulus slightly distorted;Simulated weightlessness repeated exposure groups:Nishimura graded as Class2~3, 80% of the rabbits’ nucleus cells decreased,part of nucleus pulposus cells cartilaginous metaplasia; Simulated +Gz repeated exposure group:Nishimura graded as Class 2~3,70% of the rabbits’ nucleus pulposus cells decreased significantly and arranged in cell clusters,cartilaginous metaplasia obvious;Simulated weightlessness and +Gz repeated exposure group:Nishimura graded as Class 3~5,80% of the rabbits’ nucleus pulposus cells were rare and arranged in cell clustes,part of the nucleus fibrosis,the annulus cracks appeared. Each group differences were statistically significant(P <0.05). Conclusion: 1.Long-term exposure to Weightlessness and +Gz environments both can lead to reduced animal lumbar disc proteoglycan content, had degeneration performance in imaging and pathology, leading to interverterbral disc degeneration; 2. There was a positive correlation between the lumbar interverterbral disc degeneration and Weightlessness and +Gz environment exposure time;3.The weightlessness and +Gz environment have a synergistic effect on lumbar intervertebral disc degeneration, and degeneration is greater than the single weightlessness and +Gz conditions.Objective:Evaluation of the efficacy of the mid-term treatment of unicompartmental knee arthroplasty single compartment osteoarthritis,and discuss its indications and so on.Methods: A retrospective analysis from January 2010 to December 2012 at PLA Air Force General Hospital in preoperative imaging and arthroscopy diagnosed with medial compartment knee osteoarthritis and underwent unicompartmental knee arthroplasty surgery,a total of 20 cases patients(21 knees). 17 patients(18 knees) get a return visit(16 female, 1 male), 3 cases were lost, returning 85%.The patients aged from 49-71 years old,the mean age was 56 years old. Prosthesis manufactured by the German Link company Endo-model Sledge type, and assessed preoperative and postoperative 2 years of knee flexion, KSS score and HSS score,evaluation of mid-term clinical efficacy of unicompartmental knee arthroplasty. The results of the preoperative and postoperative scores were paired t test, P <0.05 considered statistically significant.Results: Preoperative HSS score was 55 ± 6.7, after 2 years in patients with HSS score was 90.5 ± 4.4, preoperative and postoperative HSS score difference was statistically significant(P <0.05); Preoperative KSS score was 52.5 ± 5.5, after 2 years in patients with KSS score was 93 ± 2.9, preoperative and postoperative KSS score difference was statistically significant(P <0.05); Preoperative knee flexion was 90 ± 13.7, after 2 years in patients with knee flexion was 127.2 ± 6.9, preoperative and postoperative knee flexion difference was statistically significant(P <0.05).Conclusion:Unicompartmental knee arthroplasty for the treatment of medial compartment osteoarthritis achieved good clinical efficacy, and has been praised in patients. Estimated in the treatment of patients with single compartment osteoarthritis will have a wider range of applications. |
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