组织工程骨体内植入运动与感觉神经束后的成骨效果

Osteogenesis effects of tissue-engineered bone after sensory and motor nerve tract implantations

目的:用放射学方法评估和比较两种组织工程骨体内神经支配重建方法的成骨效果,探讨神经化与成骨的相互关系。方法:实验于2003-12/2005-03在南方医科大学南方医院动物所完成。20只新西兰大白兔随机分成3组:组织工程骨组、感觉神经束植入组、运动神经束植入组,每组6只。另2只兔作为骨缺损空白组。①除骨缺损空白组外,其余3组兔均制备组织工程骨。②各组兔均建立股骨1.5cm长骨缺损模型。③组织工程骨组于骨缺损处只嵌入β-磷酸三钙+经诱导分化的骨髓基质细胞复合物;感觉神经束植入组将隐神经束植入β-磷酸三钙+经诱导分化的骨髓基质细胞复合物的侧槽内;运动神经束植入组将股神经束植入β-磷酸三钙+经诱导分化的骨髓基质细胞复合物的侧槽内并加以固定;骨缺损空白组骨缺损内不植入任何材料。④术后4,8,12周除骨缺损空白组外各组处死2只兔,观察组织工程骨的表面变化、内痂形成、骨缺损修复情况及周围组织反应。摄股骨正位X射线片,用放射影像学评分和X射线阻射影分析比较骨缺损修复情况。骨缺损空白组于术后12和18周各处死1只,摄片观察骨缺损愈合情况。结果:实验兔20只均进入结果分析。①术后各组X射线片观察结果:组织工程骨组、运动神经束植入组在术后4,8,12周时,骨缺损区阻射影、材料吸收变化、截骨端愈合情况大体类似,感觉神经束植入组在各时间点的成骨量与骨痂塑形均较组织工程骨组、运动神经束植入组出现早且截骨端愈合快。②术后各组植入修复骨缺损的放射影像学评分结果:感觉神经束植入组正位照片骨缺损修复评分在4,8,12周均较组织工程骨组、运动神经束植入组的放射影像学评分为优犤4周:(8.333±0.816),(5.333±0.517),(5.500±0.836)分;8周:(11.333±0.516),(7.166±0.408),(8.167±0.307)分;12周:(12.500±0.894),(9.083±0.376),(10.083±0.801)分,P<0.05犦,但组织工程骨组、运动神经束植入组间无明显差异(P>0.05)。③术后各组植入骨缺损阻射密度测量值的比较:感觉神经束植入组在4,8,12周的骨缺损阻射密度相对值均大于组织工程骨组、运动神经束植入组(4周:58.663±2.541,43.501±2.725,44.578±2.948;8周:62.375±0.992,54.638±1.265,54.203±1.556;12周:84.582±1.017,71.683±2.101,73.585±1.975,P<0.05),但组织工程骨组、运动神经束植入组间差异不明显(P>0.05)。结论:利用感觉神经束植入的方法可以提高组织工程骨的成骨作用,而植入运动神经束却无此作用。

AIM：To evaluate and compare the osteogenesis effects of two reconstrnction methods of tissue-engineered bone＇s innervation in vivo by roentgenographic analysis, and explore the interrelation of neurotization and osteogenesis. METHODS：The experiment was conducted from December 2003 to March 2005 at the Animal Institute of Nanfang Hospital, Southern Medical University. Twenty New Zealand rabbits were divided into 3 groups randomly： tissue-engineered bone group （A）, sensory nerve tract implanted group （B）, motor nerve tract implanted group（C）, with 6 in each group, and another two rabbits were taken as bone defect blank group. ①Eighteen rabbits of group A, B and C were prepared with tissue-engineered bone except for the two rabbits in blank group. ②A femur defects model of 1.5 cm long was made in each rabbit of 4 groups. ③Group A： The composite of beta-tricalcium phosphate （β-TCP） seeded into the differentiated hone marrow stroma cells （BMSCs） by induction were implanted into the bone defects; Group B： The saphenous nerve tracts were implanted into the lateral trough of the cell-scaffold composite of β-TCP and differentiated BMSCs by induction; Group C： The femoral nerve tracts were implanted into the lateral trough of the cell-scaffold composite of β-TCP and differentiated BMSCs by induction, and then fixed; Blank group： Bone defects were implanted nothing. ③ At the 4^th, 8^th and 12^th weeks postoperatively, two animals from each group were killed except blank group. The external changes, formation of interior callus, repair of bone defects and response of surrounding tissues were observed in the tissue-engineered bone. Anteroposterior radiographs of the left femur were made on computer digital scan. Repair of bone defects was analyzed by radiographic scoring system and X-ray blocking projective analysis. As for the blank group, rabbit was executed respectively at the 12^th and 18^th weeks, and healing effects of bone defects were observed by taking radiographs. RESULTS： Twenty experimental rabbits were all involved into the result analysis. ①Postoperative observations with X-ray： At the 4^th, 8^th and 12^th weeks postoperatively, the blocking projection, change of materials＇absorption and healing effects of osteotomy in bone defects were similar in group A and group C, And osteogenetic amount and bony callus moulding at different time points all appeared early in group B compared with other two groups, with the quick healing of cut extremities.②Radiographic scores of repaired bone defects： At the 4^th, 8^th and 12^th weeks, the scores of repaired bone defects in group B were higher than both those of group A and group C [4^th week： （8.333±0.816）, （5.333±0.517）, （5.500±0,836） score; 8^th week： （11.333±0.516）, （7.166±0.408）, （8.167±0.307） score; 12^th week： （12.500±0.894）, （9.083±0.376）, （10.083±0.801） score, P 〈 0.05], There was no significant difference between group A and group C （P 〉 0.05）. ③ Comparison of measured values of relative bone density： The values of bone defects in group B were higher than both those of group A and group C （4^th week： 58.663±2,541, 43.501±2.725, 44.578±2.948; 8^th week： 62.375±0.992, 54.638±1.265, 54.203±1.556; 12^th week： 84.582±1.017, 71.683±2.101, 73.585±1.975,P 〈 0.05）. with the insignificant difference between group A and group C （P 〉 0.05）, CONCLUSION：Implantation of sensory nerve tract can improve osteogenesis of tissue-engineered bone, while the motor nerve tract implantation is ineffective.