小鼠体内异种骨移植局部肿瘤坏死因子α基因表达及细胞定位

Gene expression and cellular localizations of tumor necrosis factor α in the area of implanted xenogeneic bone in mice

目的：观察肿瘤坏死因子α（ＴＮＦα）在异种骨移植局部的表达及细胞定位．方法：将经过一定化学处理的牛松质骨载体植入小鼠股部肌袋内，于术后５，１０和２０ｄ取材，制备石蜡切片，应用原位杂交技术检测植骨局部ＴＮＦαｍＲＮＡ的表达与细胞定位．结果：①术后５，１０和２０ｄ，植骨局部均有ＴＮＦαｍＲＮＡ的阳性表达，以１０ｄ时阳性表达率最高（Ｐ＜０．０５）；②阳性反应细胞在载体周边呈散在局灶性或弥漫性分布；③阳性物质主要定位于骨粒周围的单核细胞、多核巨细胞的胞核内，部分间充质细胞、纤维母细胞和横纹肌细胞的胞浆和（或）胞核内亦有阳性表达信号．结论：ＴＮＦαｍＲＮＡ在异种骨移植局部多种细胞内出现高表达，提示ＴＮＦα可能是植骨局部细胞免疫调节的重要细胞因子之一．

Objective: To determine if mRNA encoding for tumor necrosis factor α (TNFα) is present at the site of implanted bovine cancellous bone and to observe the cellular localizations. Methods: The particles of bovine cancellous bone treated by special chemical reagents were implanted in the mouse's muscle pouch, removed 5, 10 and 20 days after implantation, and the specimens were processed for determining the mRNA expression and cellular localizations of TNFα, which was performed by a nonradioactive in situ hybridization technique. Results: (1) 5, 10 and 20 days after transplantation, the TNFα mRNA expressions were positive, and the positive rate of expression was the highest by 10 days ( P <0.05). (2) There was strong hybridization signal localization to the nuclei of morphologically identifiable monocytes and multinucleated giant cells. (3) Similar activity was detected in the cytoplasm and (or) nuclei of partial adjacent mesenchymal cells, fibroblasts as well as striated muscle fibers. Conclusion: This finding indicates that mRNA encoding for TNFα is intensely expressed in several kinds of cells and suggests that TNFα seems to be of importance for the modulation of local cellular immunity in the region of implanted xenogeneic bone.