Preliminary Study On The Expression Of BMP9 And EGFR In The Microenvironment Of Nonunion

Objective: To explore the expression changes of bone morphogenetic protein 9(BMP9)and epidermal growth factor receptor(EGFR)as well as changes of osteoblasts and osteoclasts counts in microenvironment of nonunion for the etiology and treatment of nonunion.Methods: The animal models of nonunion was built in twelve 3-months old healthy new zealand white rabbits as the experimental group and six healthy even-aged new zealand white rabbits were enrolled as the control group.X-ray examination was used to verify the result of modeling.The expressions of BMP9 and EGFR in local tissues were detected by Western-Blot and immunohistochemistry.HE staining and tartaric acid resistance staining(TRAP staining)were used for osteoblasts and osteoclasts counts.Results: The results of X-ray examination indicated that the animal models of nonunion was successfully built.The results of Western-Blot and immunohistochemistry revealed that the expressions of BMP9 and EGFRin the late stage of fracture healing were significantly lower than that in the early stage of fracture healing.Besides,the expression of BMP9 in the microenvironment of nonunion was lower than that in the control group,whereas,the expression of EGFR was not statistically different from that of the control group.HE staining and TRAP staining showed that osteoblasts in the late stage of fracture healing was significantly decreased that in the early stage.Moreover,decreased osteoblasts were also revealed in the microenvironment of nonunion.But differences were not observed in the osteoclasts counts between the early and late stages of fracture in the experimental and the control group.Conclusion:The nonunion may be associated with decreased expression of BMP9 and EGFR and decreased osteoblasts quantities in local tissues of nonunion.