模拟高原环境对大鼠骨折愈合的影响研究

Effects of a simulated plateau environment on fracture healing in rats

目的研究模拟高原环境对大鼠骨折愈合的影响。方法选取60只雄性Wistar大鼠,采用钢锯截断加克氏针髓内固定法建立大鼠股骨中段骨折模型,采用随机数字表法平均分为2组(n=30):对照组(大鼠饲养于中国人民解放军联勤保障部队第九四〇医院动物实验中心,海拔1400 m)和高原组(将大鼠放入模拟高原环境动物实验舱,模拟海拔高度5000 m)。每周称量1次体重,每2周拍摄1次X线片,第4周采集血液进行骨代谢生化指标的检测,第8周取术侧股骨进行骨生物力学检测并取健侧股骨进行骨密度检测,第4、8周取术侧股骨进行离体Micro-CT扫描、血管造影检测,第1、2、4、8周取术侧股骨进行骨组织病理学检测。结果整个实验过程中对照组大鼠无死亡,而高原组大鼠死亡率高达26.7%(8/30);且高原组大鼠部分脏器出现病理性损伤,发生骨折延迟愈合,骨痂分化成熟缓慢,第8周仍以软骨细胞为主;高原组大鼠股骨骨密度和最大载荷显著低于对照组,差异有统计学意义(P<0.05);血管造影结果显示,第8周时高原组大鼠出现了微血管增生但没有贯通骨折断端。第4周高原组大鼠的骨形成指标骨钙素、Ⅰ型原胶原氨基端肽(PⅠNP)、骨保护素显著低于对照组,同时高原组大鼠的骨吸收指标抗酒石酸酸性磷酸酶5b(TRACP-5b)及核因子κB受体活化因子配体(RANKL)则显著高于对照组,差异有统计学意义(P<0.05)。结论海拔5000 m的模拟高原环境可能会导致大鼠骨折延迟愈合。

Objective To study the effects of a simulated plateau environment on fracture healing in rats.Methods A rat model of mid-femoral fracture was established by hacksaw truncation and intramedullary fixation with Kirschner wires in 60 male Wistar rats which were divide into 2 groups(n=30)by the random number table method.The rats in the control group were raised in the animal experiment center of The 940 Hospital of Joint Logistic Support Force of Chinese PLA at an altitude of 1,400 m,while the rats in the plateau group were placed in an animal experimental cabin in a simulated plateau environment at a simulated altitude of 5,000 m.The body weight was weighed once a week and X-ray films were taken every 2 weeks.Blood samples were collected after 4 weeks for detection of biochemical indicators of bone metabolism.After 8 weeks,the femurs of the surgical side were taken for bone biomechanical detection and the bone mineral density of the healthy side was detected.After 4 and 8 weeks,the femurs of the surgical side were taken for in vitro Micro-CT scanning and angiography detection.After 1,2,4 and 8 weeks,the femurs of the surgical side were taken for bone histopathologic detection.Results During the entire experiment,no rats in the control group died while the mortality rate of the rats in the plateau group was as high as 26.7%(8/30).In the plateau group,some organs were pathologically damaged in the rats,fracture union was delayed,and the callus differentiated and matured slowly with the chondrocytes still dominant at the 8th week.The bone mineral density and the maximum load of the femur in the plateau group were significantly lower than those in the control group(P<0.05).Angiography showed that the rats in the plateau group had microvascular proliferation which did not penetrate the fracture end at the 8th week.The bone formation indexes like osteocalcin,procollagen typeⅠN-terminal propeptide(PⅠNP),and osteoprotegerin of the rats in the plateau group were significantly lower than those in the control group at the 4th week(P<0.05).The bone resorption indexes like tartrate resistant acid phosphatase 5b(TRACP-5b)and receptor activator for nuclear factor-κB ligand(RANKL)in the plateau group were significantly higher than those in the control group(P<0.05).Conclusion A simulated plateau environment at an altitude of 5,000 m may lead to delayed fracture healing in rats.