Objective To develop-the rat model of diffuse brain injury(DBI)and to observe the pathophysio logical alteration of the rats after.traumatic injury.Methods A modified Marmarou's traumatic device W88 used to establish the animal model of diffuse brain injury with different degree through changing the impact condition that was applied on the rat brain(including 80cm 450g,120 cm 450g and 180cm 400g);the animal model was evaluated by observing the variations of nervous system signs,vital signs,sensorimotor function,and morphological changes of brain tissue in the rats that have received different impacts.Results The significant changes in nervous system signs,vital signs and sensorimotor function had been observed in all rats that were subjected to the different impact.The pathologic changcs of DBI in rats brain could he found in all groups.Moreover,this characteristic changes would have became more significant following the traumatic iaiury when the impact energy was increased.Conclusion The rat model of graded diffuse brain injury have been developed successfully.The moderate impact(120cm 450g)could produce low animal death rate and result in obvious pathologieal alterations in the injured rat brain.This impact condition would be suitable to be used in the study about DBI.

Objective To explore the expression of c-fos,bcl-2,bcl-xL gene and apoptosis in rats with diffuse brain injury combination secondary injury(SBI).Methods 40 rats were randomly divided into the normal control group 10,10 cerebral ischemia,head injury group 10 and group 10 SBI to immunohistochemical method to detect brain cells in the c-fos,bcl-2,bcl-xL expression and in-situ to apoptosis(TUNEL).Results The expression of brain injury group and SBI group of cortex area c-fos gene (23.6±9.4),(37.1±5.5)positive cells/entries/H was significantly higher than that of cerebral ischemia group (5.6±1.4) positive cells/entries/H(t= 3.458,t = 3.648, all P<0.01) ;the expression of brain injury group and SBI group cortex area bcl-2 gene (18.2±4.6) ,(15.6±3.7)positive cells/entries/H lower than that brain blood group(23.6±4.3)positive cells/entries/H(t=2.345, t=2.447 ,all P <0.05) ;the expression of bcl-xL gene changes llttle;the apoptosis SBI group cortex area (36.6±5.3)cells/0.1mm2 higher than the brain injury group (21.6±4.4) cells/0.lmm2 (t = 2.378 ,P < 0.05 );the apoptosis and level of bcl-2 expression showed a negative correlation(r = -0.857 ,P <0.01 ).Conclusion The expression of c-fos,bcl-2,bcl-xL were increased with closely related to apoptosis in rats with diffuse brain injury combination secondary injury.