目的 构建小鼠甲状腺转录因子-2（TTF-2）转基因动物表达载体（pBROAD3-TTF-2），观察其在小鼠骨髓间充质干细胞（BMSC）中的表达。 方法 从C57BL/6J小鼠肝脏组织中提取基因组DNA，利用聚合酶链式反应方法扩增出TTF-2基因1 113 bp开放阅读框，通过DNA重组技术将TTF-2基因片段插入克隆载体pMD18-T中，经测序正确后，再重组于pBROAD3-mcs中，构建转基因动物表达载体pBROAD3-TTF-2，用酶切电泳分析对其进行鉴定。运用脂质体转染试剂将其转染BMSC后，蛋白质印迹法检测TTF-2基因的表达。 结果 ① DNA测序证实目的基因序列正确无突变，酶切电泳分析得到相应的目的片段，大小与理论计算值一致，成功构建转基因动物表达载体pBROAD3-TTF-2。② 蛋白质印迹法显示转染的BMSC高表达TTF-2蛋白。 结论 成功构建了pBROAD3- TTF-2转基因动物表达载体，显示其转染BMSC后TTF-2基因的表达，为下一步建立TTF-2转基因小鼠模型奠定了基础。
Objective To investigate the effect of Kartogenin (KGN) combined with adipose-derived stem cells (ADSCs) on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction in rabbits. Methods After the primary ADSCs were cultured by passaging, the 3rd generation cells were cultured with 10 μmol/L KGN solution for 72 hours. The supernatant of KGN-ADSCs was harvested and mixed with fibrin glue at a ratio of 1∶1; the 3rd generation ADSCs were mixed with fibrin glue as a control. Eighty adult New Zealand white rabbits were taken and randomly divided into 4 groups: saline group (group A), ADSCs group (group B), KGN-ADSCs group (group C), and sham-operated group (group D). After the ACL reconstruction model was prepared in groups A-C, the saline, the mixture of ADSCs and fibrin glue, and the mixture of supernatant of KGN-ADSCs and fibrin glue were injected into the tendon-bone interface and tendon gap, respectively. ACL was only exposed without other treatment in group D. The general conditions of the animals were observed after operation. At 6 and 12 weeks, the tendon-bone interface tissues and ACL specimens were taken and the tendon-bone healing was observed by HE staining, c-Jun N-terminal kinase (JNK) immunohistochemical staining, and TUNEL apoptosis assay. The fibroblasts were counted, and the positive expression rate of JNK protein and apoptosis index (AI) were measured. At the same time point, the tensile strength test was performed to measure the maximum load and the maximum tensile distance to observe the biomechanical properties. Results Twenty-eight rabbits were excluded from the study due to incision infection or death, and finally 12, 12, 12, and 16 rabbits in groups A-D were included in the study, respectively. After operation, the tendon-bone interface of groups A and B healed poorly, while group C healed well. At 6 and 12 weeks, the number of fibroblasts and positive expression rate of JNK protein in group C were significantly higher than those of groups A, B, and D (P<0.05). Compared with 6 weeks, the number of fibroblasts gradually decreased and the positive expression rate of JNK protein and AI decreased in group C at 12 weeks after operation, with significant differences (P<0.05). Biomechanical tests showed that the maximum loads at 6 and 12 weeks after operation in group C were higher than in groups A and B, but lower than those in group D, while the maximum tensile distance results were opposite, but the differences between groups were significant (P<0.05). Conclusion After ACL reconstruction, local injection of a mixture of KGN-ADSCs and fibrin glue can promote the tendon-bone healing and enhance the mechanical strength and tensile resistance of the tendon-bone interface.