Impacts Of Long Bone Fracture On Traumatic Brain Injury Of CD1 Mice

Objective:Traumatic brain injury(TBI)which characterized by high morbidity and high mortality is a common disease of neurosurgery.According to the injury time,type and severity level,TBI can be divided into various types.Depending on different areas and extents of the brain damage,TBI can cause cognitive,sensory processing,motor execution,verbal communication damages Which exhibit in behavioral or psychological aspects.The mainly reasons which caused TBI are traffic accidents,falling from height,tripped,firearm-related injuries and so on.Traffic accidents,falling from height in causing brain injuries are also associated with some other injuries,which fractures are one of the common injury.Long bone fractures(LBF)refers to the destruction of bone continuity or completeness.Patients with traumatic brain injury associated with fractures are not uncommon in clinics.,which not only caused agony to patients and their families,also caused quite a burden to society.This study applied the free-fall weight-dropping model of TBI by which CD1 mice TBI models was established,using the forceps crushing models to build the LBF models.This study by using the dry-wet weight method to detect the cerebral edema,and by using the neurological severity scores and neurological behavioral experiments to observe the behavioral changes after TBI and LBF over time,tries to clarify the molecular mechanisms,and provides experimental basis for clinical treatment of in patients both with traumatic brain injury and long bone fractures.Methods:1 75 CD1 adult male mice which were all clean grade and weighted 35 g to 45 g were randomly divided into normal control group,TBI group and LBF with TBI group.By using the free-fall weight-dropping model to establish the TBI model,and using the forceps crushing models to build the LBF models.15 mice were classified into normal control group,whose head skin was cut open to expose the parietal bone and then sutured;30 mice were classified into TBI group.These mice were exposed the left parietal bone by cutting the head skin,whose head was fixed on an anvil to make sure the left parietal bone and the anvil was parallel and was perpendicular to the organic glass tube.Then drop a 10 g weight cylindrical objects whose diameter was slightly smaller than the organic glass tube form 25 cm high to hit the exposure skull's parallel position in the mean while avoid the re-bouncing injury.In the end suture the scalp carefully.There were 30 mice in the TBI with LBF group which were build the TBI model first then were broken their right tibia and fibula by hemostatic forceps to make the LBF model.2 Score the same 5 mice form each group after been processed in 1 hours,4 hours,24 hours,3 days and 7 days with neurological severity scores(NSS).The TBI group and the TBI with LBF group went though the open field test in 3 days before intervention and 7 days,14 days and 21 days after intervention,in the mean while ran the the elevated plus maze test in 14 days and 21 days after the intervention.Except the normal control group,the other 2 groups each separate 3 mice at a time by using the dry-wet weight method to mensurate the degree of brain edema in 12 hours,1 days,3 days,5 days,7 days after intervention.In each group we separated 5 mice at a time which was taken out of brain and perfused with paraformaldehyde to carry out the immunohistochemical experiment in 7 days,14 days,21 days after intervention.The immunohistochemical experiment is to observe the glial fibrillary acidic protein' antibodies' expression in the cerebral cortex of the mice.Analysis images By using the pathology image analysis system of image processing software image-pro plus 6.0 analysis the pathological section to observe the changes in cerebral cortex.And use the SPSS 21.0 software to obtain and analysis the statistical data.Results: 1 General condition: The mice of the normal control group were in good mentality and activities,and ate well;The mice of the TBI group and TBI with LBF group behaved in somnolence,loss of appetite and activities,loss of appetite.The general condition was improved about 7 days later after intervention,while was still worse than the normal control group.2 Behavioral experiments: 2.1 NSS: The trend of each group's NSS which changed along with each time point was different.Comparing any two team of the three at each time point we found remarkable differences.The NSS of the TBI with LBF group was higher than the TBI group,while both of which were higher than the normal control group;2.2 Open field experiment: 2.2.1 the average overall velocity: The TBI group was better than the TBI with LBF group.The trends decreased significantly after the intervention and recovered slightly beyond 7 days.2.2.2 The central regional activity time: There was no significant difference between the two groups.The trends which decreased rapidly after intervention decreased slowly after 7days.2.2.3 The corner regional activity time:The comparison between the two groups had no significant difference.The trends were on rise after intervention,while declined beyond 14 days.2.3 The elevated plus maze 2.3.1 14 The total numbers into the arm at 14 th day: There were no significant difference between the two groups.2.3.2 The total numbers into the arm at 21 th day: Compared the two groups there was a significant difference as the mice of TBI with LBF group acted worse than those of the TBI group.3 Dry-wet weight method: In each group the water content of the brain tissue reached the peak at about 3 days after the intervention.There was no significant difference between the two groups in the trauma side of the brain tissue.4 The immunohistochemical experiment: The number of the GFAP positive cells in each group has statistical difference.The number of the GFAP positive cells in the control group did not change over time,and the number of GFAP positive cells in the experimental group showed a downward trend over time.Conclusions:1 The TBI can result in some significant cognitive and motor function damage in CD1 mice,while the motor function damage could be increased by the LBF.2 The LBF increased the anxiety of the TBI mice on the 21 th day.3 The TBI caused brain edema reached the peak around the 3th day after the intervention.4 The TBI can cause inflammation and neuronal death in brain tissue of CD1 mice which decreased gradually after 7 days,while the LBF can aggravate the inflammatory reaction.In conclusion,the LBF aggravated the inflammatory response of the CD1 mice which with TBI in the brain tissue,resulting in greater mental and physical impairment.