背景:脊髓损伤后早期可发生一系列代谢和内分泌的变化,表现为骨吸收活跃,骨形成相对减少.在脊髓损伤早期通过测定血尿中这些物质的含量,间接了解骨代谢的情况,对识别和判定脊髓损伤早期骨质疏松的危险性有重要意义.目的:观察豚鼠脊髓损伤早期骨代谢指标和骨量的变化,探讨脊髓损伤对骨代谢的影响.设计:随机对照动物实验.单位:复旦大学附属中山医院康复医学科.材料:实验于2004-03在复旦大学附属中山医院康复医学研究所完成.健康雄性豚鼠23只,体质量427～710 g,平均570 g,由复旦大学附属中山医院实验动物中心提供.将豚鼠随机分为实验组(造成脊髓损伤模型)10只,对照组13只,两组用标准饲料在相同环境下饲养2周.方法:以显微外科手术小剪刀切割实验组豚鼠脊髓1.5 mm,术后30 min苏醒后,可见双下肢硬瘫,肌张力高,双下肢浅深感觉消失,但尿便无失禁;对照组假手术但同样暴露脊髓后直接关闭.两组用标准饲料在相同环境下饲养2周.收集两组实验动物的尿液、血清和胫骨标本,测定血清骨碱性磷酸酶、尿吡啶酚/肌酐、尿钙/尿肌酐值.两样本间用t检验及H检验分析.主要观察指标:①两组实验动物骨密度及骨干重灰重比较.②两组实验动物骨形成的生化指标比较.结果:两组各有10只动物纳入结果分析.①两组实验动物骨密度及骨干重灰重比较:两组的骨密度、骨干重差别无显著性意义(P＞0.05);实验组骨灰重值较对照组小[(0.284±0.050)和(0.361±0.064)mg],两组间差异有显著性意义(t=3.254,P＜0.05).②两组实验动物骨形成的生化指标比较:实验组骨碱性磷酸酶值较对照组小[(0.640±0.240)和(1.328±0.606)U/L],两组间差异有显著性意义(H=9.499,P＜0.05);实验组尿吡啶酚/肌酐值和尿钙/尿肌酐值均较对照组大(尿吡啶酚/肌酐:0.206±0.080和0.117±0.037;尿钙/尿肌酐:0.003±0.003和0.002±0.002),两组间差异有显著性意义(H=9.676,4.124,P＜0.05).结论:脊髓损伤早期可出现骨质吸收加速,并影响成骨细胞的骨形成功能,早期即可发生骨代谢异常.早期识别骨代谢异常是防治脊髓损伤后并发症的重要关键因素,骨代谢生化指标对脊髓损伤早期骨质疏松危险性的评估有较大的意义.%BACKGROUND: In the early stage following spinal cord injury, a series of changes in metabolism and secretion take place, such as accelerated bone resorption and decreased bone formation. Determination of the biochemical markers of bone metabolism early after spinal cord injury may help understand the metabolic changes and facilitate risk evaluation for osteoporosis on such occasion.OBJECTIVE: To study the earlychanges of bone mass and bone metabolism indices in guinea pigs with spinal cord injury and evaluate the impact of spinal cord injury on bone metabolism.DESIGN: Randomly controlled animal experiment. SETTING: Department of Rehabilitation Medicine, Zhongshan Hospital of Fudan UniversityMATERIALS: The experiment was conducted in the Institute of Rehabilitation Medicine, Zhongshan Hospital of Fudan University in March 2004. Twenty-three male guinea pigs with body weight of 427-710 g (averaging 570 g) were provided by the Experimental Animal Center,Zhongshan Hospital of Fudan University and divided into experimental group (n=10) and normal control group (n=13). All the guinea pigs were kept under the same environment and fed with standard food for two weeks.METHODS: Small microsurgery scissors was used to induce a 1.5-mm transverse incision of the spinal cord, with the bleeding carefully managed and the wound closed. Thirty minutes after surgery, the guinea pigs recovered consciousness with bilateral lower limb paralysis (hypertonic paraplegia) and loss of superficial and deep sensations, but without urinary and fecal incontinence. The animals in the control group had sham operation. After housing in the same environment with standard food for 2 weeks, urine,serum and shinbone samples were collected from the animals for measurement of serum bone alkaline phosphatase (BALP), urinary pyridinoline (Pyd)/creatinine (Cr) and Ca/Cr. t test and H test were used for comparison of the samples between the two groups.parison of biochemical markers for bone formation between the two groups.RESULTS: Ten animals were analyzed in each group. No significant difference was observed in the BMD and bone dry weight between the two groups (P ＞ 0.05), but the bone ash weight of experimental group was remarkably lower than that of the control group [(0.284±0.050) vs (0.361±0.064) mg, t=3.254, P ＜ 0.05). The experimental group had significantly lower serum BALP than the control group [(0.640±0.240)vs (1.328±0.606) U/L, H=9.499, P ＜ 0.05), but higher urinary Pyd/Cr [(0.206±0.080) vs (0.117±0.037), P ＜ 0.01) and Ca/Cr [(0.003±0.003)vs (0.002±0.002), P ＜ 0.05] than the control group (H=9.676, 4.124,P ＜ 0.05).CONCLUSION: After the spinal cord injury, bone resorption remarkably increases and the function of the osteoblasts is inhibited. Bone metabolic abnormalities can occur in the early stage of spinal cord injury, and the biochemical indices for bone metabolism are sensitive in evaluating the risks for osteoporosis after spinal cord injury.
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