脑损伤并股骨骨折愈合患者骨痂中骨形态发生蛋白2和胰岛素样生长因子1的表达

Expressions of bone morphogenetic protein-2 and insulin-like growth factor-1 in callus of brain injury patients following fracture healing of the femur

背景:临床观察及基础研究发现,合并颅脑损伤可加速骨折愈合,但具体机制尚不明确。目的:观察脑损伤后SD大鼠股骨骨折愈合过程中骨痂骨形态发生蛋白2和胰岛素样生长因子1的表达,探讨脑损伤对大鼠股骨骨折愈合的影响及其作用机制。设计、时间及地点:随机对照,基因水平动物实验,于2007-05/2008-03在华北煤炭医学院骨科实验室完成。材料:SPF级10周龄雄性SD大鼠48只。方法:48只SD大鼠随机分成2组,每组24只。参考文献建立大鼠单纯股骨骨折模型和脑损伤合并股骨骨折模型。于术后7,14,28d分批处死动物,行X射线摄片后,取股骨骨痂,分别用于提取总RNA进行实时荧光定量聚合酶链反应。主要观察指标:以X射线摄片观察骨折愈合情况;以苏木精-伊红染色、免疫组织化学染色观察骨痂组织骨形态发生蛋白2和胰岛素样生长因子1的表达。结果:X射线摄片示,与单纯骨折组相比,骨折合并脑损伤组骨痂出现早,同一时间骨痂更大。免疫组织化学显示,造模7,14d脑损伤合并股骨骨折组骨形态发生蛋白2、胰岛素样生长因子1的平均阳性细胞百分率高于单纯骨折组。实时荧光定量聚合酶链反应结果发现,脑损伤合并股骨骨折组7,14d骨形态发生蛋白2基因mRNA表达高于单纯骨折组,7,14,21d胰岛素样生长因子1基因mRNA表达高于单纯骨折组。结论:与单纯骨折组相比,骨折合并脑损伤组大鼠骨折愈合加速,骨痂中骨形态发生蛋白2和胰岛素样生长因子1的表达显著性升高,提示脑损伤促进了骨折愈合的机制可能与此有关。

BACKGROUND： Many clinical observations and basic researches have reported that fracture healing could be accelerated when coupled with brain injury, but the mechanism is unclear. OBJECTIVE： To investigate the expression of bone morphogenetic protein-2 （BMP-2） and insulin-like growth factor-1 （IGF-1） in callus of rats after femoral fracture with or without brain injury, and to analyze the effects and mechanism of brain injury on fracture healing. DESIGH, TIME AND SETTING： A randomized controlled animal experiment was conducted in the laboratory of Orthopedic, the Affiliated Hospital of North China Coal Medical University from May 2007 to March 2008. MATERIALS： Forty-eight SPF classic male SD rats aging 10 weeks. METHODS： Forty-eight male SD rats were randomly divided into 2 groups with 24 rats in each group ： ① Femoral fracture group （n=24）.②Femoral fracture and brain injury group （n=24）. Fracture and brain injury models were established. The rats were sacrificed at the 7th, 14th, 21st days postsurgery, after the X-ray detection, callus were extracted and used for extracting mRNA and performing real-time fluorescence quantitative polymerase chain reaction. MAIN OUTCOME MEASURES： The X-ray film was applied to observe fracture healing; expressions of BMP-2 and IGF-1 in callus were detected. RESULTS： The X-ray films showed that the callus formation in the femoral fracture and brain injury group was earlier and greater than that in the pure femoral fracture groups at the same time point. The immunohistochemistry showed that the mean cell positive rates of BMP-2 and IGF-1 in fracture with brain injury group at the 7th and 14th days were higher than those in femoral fracture group. The fluorescence quantitative polymerase chain reaction showed that the mRNA expression levels of BMP-2 and IGF-1 were significantly higher than those in femoral Fracture group. CONCLUSION： Compared with the pure femoral fracture, brain injury could accelerate the rat femoral fracture healing; the upregulation of BMP-2 and IGF-1 in callus might participate in this process.