Establishment Of A Rat Model Of Mechanical Stress Induced Acute Brain Injury And The Pathological Changes Of Nerve Fiber Bundle In The Basal Ganglia Area

BackgroundSpontaneous intracerebral haemorrhage(s ICH),related sudden intracranial vascular rupture without any brain trauma,has the highest morbidity and mortality of all stroke,and the role of surgery remains controversial.The cerebral injury of the s ICH include primary injury and secondary injury.In the acute phase of primary injury,the mechanical stress to brain tissue produced by hematoma is the main cause of injury to the perihematoma.However,there is few studies about the mechanical stress by hematoma during intracerebral hemorrhage at home and abroad.One of the most considerable reasons is the blank of a stable and effective animal model.ObjectiveTo establish the model of cerebral stress injury in acute cerebral hemorrhage in rats,observe the neurological function score and pathological changes,and evaluate the accuracy,repeatability and consistency of the model.MethodsSixty-five male SD rats were randomly divided into sham operation group(n=15),25?l balloon group(n=25)and 50?l balloon group(n=25).Three different size of empty flat balloon(50?l,25?l,50?l)were implanted into the basal ganglia respectively.When the rats wake up from anesthesia,neuro-behavior was recorded by Longa Neuro-behavioral Score.The behavioral changes(Longa Neuro-behavioral Score?1)were eliminated.The rats were brought into the experiment group(sham group n=10,25?l balloon group n=10,50miu?l balloon group n=10)with the balloon which were inflated in 10 s by pressure pump to mimic the acute intracerebral hemorrhage.Survival rate and neurological behavioral changes in 24 h were analyzed.Others(sham group n=5,25?l balloon group n=5,50?l balloon group n=5)in the experiment group were analyzed by Magnetic Resonance Imaging(MRI)T2 weighted image,Diffusion tensor imaging(DTI),Hematoxylin and Eosin stain(HE)staining,iron-hematoxylin stainingandimmunohistochemical staining.The model's accuracy,stability and repeatability,as well as the injury of the nerve fiber bundle of basal ganglia were evaluated by these methods above.ResultsThe rat model of acute mechanical stress injury of brain was successfully established.The survival rates of three groups,sham operated group,25?l and 50?l balloon group,in 24 h were 100%,90%,0% and three,respectively(P<0.01).After inflation of the balloon,there was a significant difference between the three groups(P<0.01).The bigger volume of the balloon the more serious injury of the neuro-behavioral.MRI T2 weighted images and HE staining showed that the brain injury area of 50?l balloon group was larger than 25?l balloon group(P<0.01).Iron hematoxylin staining,DTI and MBP immuno-fluorescence staining showed that nerve fiber bundle(NFB)damage ratio in 50?l balloon group was more serious than 25?l balloon group(P<0.01).ConclusionsThe acute mechanical stress brain injury rat model can simulate the mechanical stress injury in acute phase of intracerebral hemorrhage.In the acute phase of cerebral hemorrhage,mechanical stress injury leads to nerve fiber bundle injury,and the degree of injury is related to the duration of the injury and the size of the balloon.