| Objective:1. To establish the model of intracerebral internal capsule hemorrhage of rats;2. Using somatosensory evoked potential technique to evaluate the model of intracerebral internal capsule hemorrhage of rats;3. To explore the changes of electrointestinogram after internal capsule -hemorrhage and reveal the changes of gastrointestinal function through exploring the changes of SEP before and after internal capsule hemorrhage, and make an important reference for etiopathogenesis of internal capsule hemorrhage.Methods:1. Preparation of intracerebral internal capsule hemorrhagic animal model: Anesthetized rats, fix it on the rats stereotaxis instrument. According to the rats brain stereotaxic atlas, located the hind limb of internal capsule through stereotaxis instrument. An operation was made to open the skull by auger, 150μl autologous venous blood from tail was injected into the hind limb of internal capsule through microinjector, and made the acute internal capsule hemorrhage animal model.2. Ethology evaluation before and after internal capsule hemorrhage: Using two ways to detect the rat's behavior 24 hours after the operation:2.1Bederson's scoring criteria: Rats were held gently by the tail, suspended 10cm above the floor. Normal rats extend both forelimbs toward the floor. Rats that extended both forelimbs toward the floor and that had no other neurological deficit were assigned grade O. Rats that with infarction consistently flexed the forelimb contralateral to the injured hemisphere and that had posture with extension to the earth were assigned grade 1 ;rats with 1 score sign had consistently reduced resistance to lateral push toward the paretic side, and were graded 2 ; Rats were then allowed to move about freely and were observed for circling behavior. Rats that circled toward the paretic side consistently were graded 3(pursuiting tail).2.2 Vibrissae-elicited forelimb placing test:Rats were held by their torsos, which allowed the forelimb to hang free . Independent testing of each forelimb was induced by brushing the respective vibrissae on the corner edge of a countertop.Intact animals place the forelimb ipsilateral to the stimulated vibrissae quickly onto the countertop.Depending on the extent of injury,placing of the forelimb contralateral to the injury in response to contralateral vibrissae contact with countertop may be impaired.In the experiments each rat was tested 10 times for each forelimb,and the percentage of trials in which the rat placed the appropriate forelimb on the edge of the countertop in response to the vibrissae stimulation was determined.3. Measurement of SEP before and after internal capsule hemorrhage: Located the site in cerebral cortex, which was the projection of sensation of rat's left leg, through stereotaxis instrument, and this was the recording point of SEP. Found the site and perforated through the bones of skull .Connected recording electrode, reference electrode, ground electrode, exciting electrode with RM-6240B biological signal collecting and processing system, measured rat's SEP before and after internal capsule hemorrhage.4. Measurement of intestine electric activity: Absoluted diet for 12 hours, rout anesthesia, gave laparotomy on median ventral, exposed jejunal, put electrode with two needles into ectoptygma, and the distance between two needles was about 2mm.Connected with BL-410 biological function experimental system, and measured jejunal electric activity during digestion period of both control group and brain hemorrhage group 24 hours after the operation.5. Preparation of pathological specimen of rat's brain tissue after internal capsule hemorrhage and pathomorphological observation of rat's brain tissue before and after internal capsule hemorrhage: After finishing the preparation of internal capsule hemorrhage animal model, took the brain tissue, fix them with 10% formaldehyde solution; paraffin embed, make coronal plane sections on internalcapsule hemorrhage area . Through HE stain, observed their pathomorphologicalchanges under the light microscope.6. Statistical analysis: Statistical software SPSS 13.0 was used. The differences ofSEP before and after internal capsule hemorrhage were compared by paired t test;differences of intestine electric activity in control group and brain hemorrhagegroup were compared by analysis of variance (ANOVA)Results:1. The ethology test of the model of intracerebral internal capsule hemorrhage of rats through inject its autologus arterial blood: Bederson scoring:22% rats scored at 3,66% rats scored at 2,12% rats get 1; vibrissae-elicited forelimb placing test : In brain hemorrhage group, achievement ratio was 34%, achievement ratio was 98%.It suggested that there were obvious allocinesia functional disturbance on rats after internal capsule hemorrhage.2. We confirmed that the hematoma were in the hind limb of internal capsule accurately through specimens and pathological section. We observed through light microscope after internal capsule hemorrhage that the position of hematoma was full of red blood cells and inflammatory cells infiltration around; and there were cell spaces distention and cellular swelling in the perienchyma of the hematoma, which suggested the happening of cerebral edema.3. Comparison of the changes of SEP before and after internal capsule hemorrhage. The Interpeak latency of N1 to P1 of SEP were prolonged after internal capsule hemorrhage than before hemorrhage (P<0.05). The amplitude of peak to peak value were decreased than before hemorrhage (P<0.05).4. By the analysis of the changes of intestine electric activity in control group and brain hemorrhage group 24 hours after the operation ,we could find that migrating myoelectrical complex disappeared and intestine electric activity were inhibited or strengthened .They appeared to be reduction or enhancement of the action potential ,in which 52.7% were strengthened and 47.3% were weakened.Conclusions:1. We can copy the accurate model of intracerebral internal capsule hemorrhage of rats by means of stereotactic method successfully. 2. SEP is a convenient, cheap and objective index to evaluate model of intracerebral internal capsule hemorrhage. By measurement and analysis of changes of SEP in short latency before and after internal capsule hemorrhage, we can evaluate the impaired degree of nervous function objectively.3. Intestine electric activity after brain hemorrhage is abnormal. The appearance is mainly the disorder of intestine electric activity. That means migrating myoelectrical complex disappears and through persistence time of action potential group it appears to be augmentation or inhibition of normal electric activity. The result suggests that damage of central nervous system has significant effect on enteral smooth muscle's electric activity by action potential in alimentary tract. These affect maybe the electrophysiological foundation that lead to the injury of alimentary tract mucosa and stress ulcer.
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