犬同种异体气管移植中骨形成蛋白-2对气管软骨碱性磷酸酶的影响

Experimental study of bone morphogenetic protein-2 affecting cartilage alkaline phosphatases in dog's allo-transplanted trachea

目的:明确局部应用骨形成蛋白2(BMP2)对犬同种异体移植段气管碱性磷酸酶(ALP)活性的影响.方法:将西安地区健康雄性杂种犬40只随机平均分为实验组与对照组,两组间动物各取一6环颈段气管,交换后原位移植,应用犬双侧胸骨舌骨肌-胸骨甲状肌联合肌瓣包裹移植段气管提供良好血运,试验组在移植段气管环间注射BMP2/I型胶原复合物,对照组仅注射I型胶原作为空白对照,术后2,4,8,1wk分别处死实验动物,取移植段气管标本,观察其大体形态HE染色观察软骨环的微观变化;改良钙钴法测定移植段软骨组织中碱性磷酸酶的分布.结果:术后4wk后实验组移植段气管通畅度高于对照组(0.84±0.04,P<0.05);HE染色发现各个时间点两组移植段软骨细胞密度无显著性差异(P>0.05);应用图像分析软件计算切片染色阳性的像素面积,发现在术后8wk及以前,试验组动物的碱性磷酸酶染色阳性面积比例明显高于对照组(0.29±0.02,P<0.05),术后12wk两者的差别无统计学意义(P>0.05).结论:BMP2可以提高移植段气管软骨碱性磷酸酶表达,增强气管软骨的钙化,维持移植段气管环状软骨形态及气管环的稳定,为临床应用同种异体气管移植解决大段气管缺失奠定基础.

AIM: To observe local application of bone morphogenetic protein-2(BMP-2) affecting the activity of cartilage Alkaline phosphatase-2(ALP-2) in dog's allo-transplanted trachea. METHODS: Forty male mongrel dogs were randomly and equally divided into experiment group and control group. A six ring cervical tracheal segment was harvested from one dog of each group and exchanged, packed within muscle flaps of sternohyoideus-sternothyroid for blood supply in situ. Between cricoid cartilages we injected BMP-2/collagen I(experiment group) or collagen I(control group). The animals were sacrificed 2,4,8,12 weeks postoperatively, postmortem specimens were harvested and examined, HE and improved Ca-Co methods were applied histochemically to observe the exchange of tracheal cartilage and distribution of ALP. RESULTS: we found that after 4 weeks postoperatively, the transplanted trachea's unobstration degree was higher in experiment group (0.84±0.04,P<0.05). There is no significant difference between two groups in cartilage cell density(P>0.05). By calculating the positive-stained pixel in the image of tissue sections ,we compared the difference in the ratio of ALP disposition between two groups before 8 weeks postoperatively, experiment group has more ALP (0.29±0.02,P<0.05l) than control group; while no statistic difference was found between two groups at 12 weeks postoperatively(P>0.05). CONCLUSION: Local application of BMP-2 may up-regulate the ALP in tracheal cartilage and then inhibiting the Absorption of tracheal cartilage.