| Objective:To investigate the changes in the expression of bone morphogenetic protein 2 (BMP-2) in serum of rats and the role BMP-2 played in healing of femoral fracture complicating cerebral trauma by the test of ELISA, and then to study the reason of enhanced osteogenesis after brain injure.Methods:To establish fracture and brain injury models with Wistar rats.128 adult female Wistar rats were selected and randomly divided into 4 groups. The Group A was normal control. The rats in Group B had a traumatic brain injury. The rats in Group C had a femoral fracture. The rats in Group D had femoral fracture combined with traumatic brain injury. Every group contain 40 rats except Group A which only had 8.The model of brain injury were established according to the modified Feeney (caused by a falling of 20g standard weight from 30cm high through a tube onto the dura mater of brain behind the bregma.Establishing the model of femoral fracture:to expose one side of femoral, and Kirschner wire of 1.5mm in diameter was used for fixation after the middle of femoral were made fracture by saw. The blood serum of eight rats in Group A were collected in the third day, and eight rats in rest of each group were sacrificed and blood serum collected in the first day, third day, first week, second week and third week respectively after operation, and then the BMP-2 concentration in serum was detected by the test of ELISA. The rats in Group C and D which were put to death in the first, second and third week were examined with X-rays to observe the reparative process. Results:â‘ The serum level of BMP-2 in the brain injury group was higher than that of normal control group in the third day, and decreased to normal level after two weeks; The serum concentration of BMP-2 in the femoral fracture group was not increase too much in first day, it began to raise in third day and reach its peak in the second week, then fell to the twice as much as the level of Group A in the three weeks after operation; The expression of BMP-2 in Group D was much higher than that of normal control group in the third day, and rose to the peak about in the first week, then maintain the concentration in a high level in second and third week after operation. The level of BMP-2 in Group D was much higher than that of Group B and Group C in every test time. There was a statistical difference between Group D and other Groups (P<0.01).â‘¡X-ray showed that the fracture line in Group C and D were both clear in first week, there was no bone callus found. In the second week, there was a few callus in Group D but no callus in Group C. In the third week, some existing callus can be seen in Group D, but fracture line was still clear. In fracture group, only a few callus existed and the fracture line was clear. The healing speed of fracture in Group D were faster than that of Group C.Conclusion:The expression of BMP-2 in serum of rats was obviously higher in healing of femoral fracture complicating cerebral trauma. it is sure that BMP-2 is one of most important humoral factors accelerating the fracture healing, which may take part in the creative of Heterotopic ossification.
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