To Establish And Study The Combined Model Of Fracture And Graded Lateral Fluid Percussion Brain Injury

Objects: To establish a bone fracture combined with graded lateral fluid percussion traumatic brain injury model with injury stabilization, better repetition, much better clinical similar that could be graded and meet the demand of experimental study, to study the correlation between the degree of the traumatic brain injury and the rate of fracture healing.Methods: Male Sprague-Dawley rats were randomized to four experimental groups: A group (controls, n = 10), B group(fracture only, n=30), C group( traumatic brain injury only , n=90), D group (traumatic brain injury combined fracture, n=126), establishing the Sprague-Dawley rat model of tibia fracture combined traumatic brain injury, traumatic brain injury model and tibia fracture model via fluid lateral percussion brain injury and opened fracture respectively, Morphological aspects of brain are analyzed via standard histopathological procedures at 3 hours and 1 day and x-ray photography to study the healing of bone fracture,the size of callus at 3,7,14,21 and 28 days and to measure the diameter of callus at the 21 and 28 days, then the callus are decalcify to be analyzed via standard histopathological procedures at 7,14,21 and 28 days.Results: Successfully established the combined tibia fracture and traumatic brain injury model, the brain tissue Hematoxylin and Eosin stain as the same as the past documents reported shows the brain injury are graded very explicitly , steadily and with better reproducibility and much comparability at 3 hours and 1 day, at 7, 14,21 and 28 days after fracture the histopathological procedures of callus and the X-ray photography show the fracture healing rate of the groups of fracture and traumatic brain injury is much faster than the fracture only group, the callus is much hard and dense, the degree of brain injury is more heavy the fracture healing rate is more faster, The diameter of callus is much more bigger with time in all groups; 21 days after fracture the diameter of callus of the B group and the mild, moderate, severe brain injury of D groups are (6.07±0.42)mm, (6.17±0.83)mm, (6.93±0.72)mm, (7.87±0.58)mm respectively, the diameter of callus of the severe brain injury of D group is much bigger than any other groups; the diameter of callus of the moderate brain injury of D group is much bigger than the mild brain injury of D group and the fracture only group, (P<0.05), the difference is significant; the diameter of callus of the mild brain injury of D group is much bigger than B group, (P>0.05),there is no difference between them; 28 days after fracture the diameter of callus of the B group and the mild, moderate, severe brain injury of D groups are (6.84±0.52)mm,(7.06±0.55)mm,(7.90±0.38)mm,(7.80±0.56)mm respectively, the diameter of callus of the severe brain injury of D group is much bigger than the mild brain injury of D group and the fracture only group; the diameter of callus of the moderate brain injury of D group is much bigger than the mild brain injury of D group and the fracture only group, (P<0.05), the difference is significant; the diameter of callus of the mild brain injury of D group is much bigger than B group,(P>0.05),there is no difference between them, the diameter of callus of the severe brain injury of D group is smaller than the moderate brain injury of D group,(P>0.05),there is no difference between them ; a positive correlation exists between the pressure of the strike and the diameter of callus, r=0.740, p<0.001.Conclusions: The combined animal model have the characterization of stable injury, better reproducibility and much comparability, could be graded and meet the demand of experimental study, is a good model to study the interactive of traumatic brain injury and fracture; the time of fracture healing with brain injury is shorter than the bone fracture only and have the identity of the clinical facts, there is a positive correlation between the degree of the traumatic brain injury and the rate of fracture healing.