GIT1发夹结构对骨折愈合过程中破骨细胞招募分化的影响

Effect of GIT1 RNA hairpin on osteoclast recruitment during fusion of fractured bone

目的探讨G蛋白偶联受体激酶结合蛋白1(GIT1)的RNA发夹结构对骨折愈合过程中破骨细胞分化的影响。方法制作闭合性大鼠左侧胫骨标准骨折模型,将40只大鼠分成两组,每组20只。对照组于骨折端注射含GIT1WT的慢病毒,实验组骨折端注射含GIT1的RNA发夹结构(GIT1-RNAh)慢病毒。用Western blot检测蛋白表达;骨折愈合7、14、21 d,用免疫组化法检测破骨细胞在骨折端的招募,免疫荧光染色方法检测骨折端的血管形成。结果对照组骨折端的骨痂内检测到GIT1蛋白的表达。实验组骨折端的骨痂内GIT1蛋白的表达明显被抑制,破骨细胞在骨折端的数量明显减少,骨折端的新生血管的形成明显被抑制。结论 GIT1-RNAh通过降低GIT1蛋白的表达抑制了破骨细胞的分化和血管形成,从而影响骨折愈合。

Objective To investigate the effect of G protein coupled receptor kinase interacting protein 1（GIT1） RNA hairpin（GIT1-RNAh） on osteoclast differentiation during fusion of fractured bone.Methods The bone fracture models were established according to Hihunen A＇s method.The mice were divided into two groups with 20 mice each.The mice in group A were injected GIT1-RNAh lentivirus and those in group C were injected GIT1 lentivirus as the controls.The protein expression was detected by Western blot.Osteoclast recruitment was detected by immunohistochemistry with tartrate resistant acid phosphatase（TRAP） stainging and angiogenesis formation was checked with PECAM-1 immunofluorence staining.Results GIT1 protein was expressed in fracture callus of the mice in group C.GIT1 protein expression was inhibited in fracture callus of the mice in group A.The osteoclast recruitment was significantly decreased and angiogenesis formation was significantly inhibited in group A compared with those in group C.Conclusion GIT1-RNAh inhibits GIT1 protein expression and interferes with osteoclast differentiation.