| Objective:The phenomenon that the fracture healing of patients with traumatic brain injury accompanied with fracture is accelerated has been an undebatable fact,but the exact factor and mechanism has not been explained definitely.Because the study about this problem is very few and most of them is about moderate traumatic brain injury,people have not connected traumatic brain injury of diffent severity with fracture .The object of this study is to establish TBI of different severity accompanied with fracture model to study TBI of different severity effecting on expression of bFGF and fracture healing in rats and to explore the mechanism of accelerated fracture healing of patients with TBI accompanied with fracture.Methods:106 male SD rats were devided into 5(normal group 5,mild TBI accompanied with fracture group 26, moderate TBI accompanied with fracture group 26, severe TBI accompanied with fracture 26,fracture only group 24) groups in random to establish TBI of different severity accompanied with fracture model .Blood specimens were collected from 4 rats selected in each group randomly through tail vein on day 1,4,week 1,2,3 and 5 after injury. Then the blood specimens were centrifuged and the level of bFGF in serum were measured by ELISA. 4 rats were sacrificed in each treat group on day 1,4,week 1,2,3 and 5 after injury(the right tibia was taken X ray photograp first to observe fracture healing process and effect) and the entire right tabia was made specimen.Local expresson of bFGF in fracture site were determined by immunohistochemical stain and the state of bone healing was examined by HE stain and radiation imageology.All data was maken statistical treatment through software SPSS11.5.Results:1 The average Serum bFGF level of normal rats was 6.22pg/ml.It raised slightly on day 4 after injury,then raised to 2.3times and 2.9 times 0f normal rats respectively at week 1,then raised to 2.8times and 2.6 times at weeks 2,then began to descend at week 3,then descended to normal level at week 5 in rats with mild TBI accompanied with fracture and fracture only and there was no significant statistical difference between the two groups(P>0.05) all the time. While it raised slightly on day 1 after injury,then it raised obviously on day 4,which was 4.9 times and 5.4 times of normal rats respectively,then it raised to its peak which was 6.8 times and 7.4 times at week 1,then began to descend at week 3,then descended to normal level at week 5 in rats with moderate and severe TBI accompanied with fracture and there was no significant statistical difference between the two groups (P>0.05) all the time,but both had significant statistical difference(P>0.01) compared with rats with mild TBI accompanied with fracture and fracture only.2 Histological observation:The fracture healing process in rats with mild TBI accompanied with fracture and fracture only was intimate,while it was about 1 week shorter in rats with moderate and severe TBI accompanied with fracture then the rats with mild TBI accompanied with fracture and fracture only. Immunohistochemical observation:There was different dgree of bFGF positive expression in the process of fracture healing in the endochylema and part of nucleus in cells such as monocyte ,fibroblast, mesenchymal, endotheliocyte, chondroc- yte, osteoblast and so on,which was obviously in chondrocyte and osteoblast. Immunohistochemical image analysis:The average count and absorbance of positive cells in rats with fracture only was 752±254 and 0.194±0.049 respectively.It was 752±245 and 0.199 in rats with mild TBI accompanied with fracture,1109±391 and 0.233±0.063 in rats with moderate TBI accompanied with fracture,1145±305 and 0.244±0.068 in rats with severe TBI accompanied with fracture respectively.There was significant statistical difference (P>0.01) in count of positive cells on day 1 and day 4 and week 1 and week 2 after injury,and in absorbance of positive cells on day 4 and week 1 after injury respectively between rats with moderate and severe TBI accompanied with fracture and ras with mild TBI accompanied with fracture and fracture only.While there was no significant statistical difference (P>0.05) between rats with moderate and severe TBI accompanied with fracture and between rats with mild TBI accompanied with fracture and fracture only.3 Radiological examination:At week 3 after injury, callus famination which was little was found in rats with mild TBI accompanied with fracture and fracture only and the fracture line was clear between broken ends of fractured bone,while more callus was found in rats with moderate and severe TBI accompanied with fracture and the fracture line was blured. At week 5 after injury, the fracture line became blured wich might be seen indistinctly in rats with mild TBI accompanied with fracture and fracture only,while great quantity of callus whose bone density was high was found in rats with moderate and severe TBI accompanied with fracture and the fracture line had disappeared.Conclusions: 1 Fracture healing of rats with moderate and severe TBI accompanied with fracture is accelerated,while mild TBI does not affect fracture healing obviously.2 The serum bFGF level of rats with moderate and severe TBI accompanied with fracture is much high,while it is slightly high in rats with mild TBI accompanied with fracture and fracture only.3 Local bFGF expression of rats with moderate and severe TBI accompanied with fracture in fracture site is enhanced,while there is no obvious difference between rats with mild TBI accompanied with fracture and fracture only.4 The frcture healing of rats with TBI of diffent severity accompanied with fracture is not identical,so it may be presumed that there is certain relation between the severity of TBI and fracture healing. |
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