一氧化氮合酶在兔下颌骨牵张成骨过程中的表达

目的：利用种植型牵张器增高兔下颌牙槽嵴，观察成骨过程中一氧化氮合酶（NOS）的表达。方法：日本大耳白兔20只，随机分为5组，分别为空白对照组，牵张后1d组、1周组、2周组和4周组，每组4只，随机选取一侧下颌骨行牵张成骨术。术后延迟4d开始牵张，每天牵张2次，共4d。处死各组兔子，游离下颌骨进行大体观察、X线观察、组织学观察和免疫组化观察，通过细胞图像分析仪测定阳性面积，利用SPSS13．0统计软件包分析诱导型NOS（iNOS）、内皮型NOS（eNOS）和神经型NOS（nNOS）的阳性表达。结果：X线及组织学检查显示，牵张间隙内新骨逐渐形成。免疫组化观察，正常骨组织NOS仅有少量的阳性表达；iNOS在间充质细胞、成骨细胞中有阳性染色，牵张后1d、1周、2周组的阳性面积显著高于正常组（P〈0．05）；eNOS在间充质细胞、增生血管内皮细胞中有阳性染色，牵张后1d、1周、2周组的阳性面积显著高于正常组（P〈0．05）；而nNOS在各实验组均无明显的阳性表达。结论：iNOS和eNOS在牵张成骨过程的不同时期具有不同的表达，提示可能对牵张成骨的新骨形成起一定的调节作用。

Expression of NOS in distracted rabbit mandibular alveolar ridge

PURPOSE: The aim of this study was to augment the mandibular alveolar ridge by implant-distraction apparatus and to determine the distribution and expression of nitric oxide synthase in distraction osteogenesis in rabbits. METHODS: Twenty rabbits were randomly divided into five groups, each with 4 rabbits. Osteotomy on the random side of the alveolar bone was carried out and an implant-distraction apparatus was placed. After 4 days, the alveolar bone was vertically distracted. At the time period of 1 day,1 week, 2 weeks and 4 weeks of DO, 4 rabbits were sacrificed. Radiographical, histological, and immunological evaluations were carried out, the change of NOS were analyzed by SPSS13.0 software package. RESULTS: Histologically, the lengthened bone consisted of mature lamellar and cancellous bone. The radiolucency in the distraction site disappeared in 4 weeks. Immunologically, little expression of iNOS and eNOS were detectable in the normal bone; the iNOS staining was localized on the mesenchymal cells, osteoblasts after DO, the expression of local iNOS was significantly stronger than that in the control group at the early period(P<0.05); the expression of eNOS was significantly higher in the mesenchymal and regenerated cells, compared with that of the normal(P<0.05); nNOS had no positive expression. CONCLUSION: iNOS and eNOS are differently expressed in various periods in DO, which indicates that they may be released and participate in promoting osteogenesis in DO.