Analysis Of Nervous Conduction Velocity Of Central Nerve Under Internal Capsule Hemorrhage Conditions In Rabbits

ObjectiveNowadays, disease incidence of cerebrovascular disease is so high that disease incidence of ICH is always at a high level. Due to especial anatomical position of internal capsule, it is usually regarded as a predilection site of ICH. Internal capsule hemorrhage is a serious neurological disease, which brings high disability rate and fatality rate. In this study, an acute internal capsule hemorrhage animal model of rabbits was established by injecting autologous arterial blood into internal capsule. The changes of pathomorphology of brain tissue and motor function of posterior limb were observed after internal capsule hemorrhage. From the fields of neurology and electrophysiology, the changes of spontaneous electrical activity of brain and SLSEP were analyzed under internal capsule hemorrhage conditions. Moreover, we explored the influence of internal capsule hemorrhage on conduction velocity of central nerve in order to provide an important reference for its early diagnosis and clinical treatmentMethods1. Subjects: The healthy male Japanese white rabbits with long ears (weighing 2.0 ± 0.2kg) were used, clean only.2. Preparation of acute internal capsule hemorrhage animal model: After anesthetization, rabbits were fixed on the stereotaxis instrument with prone position. According to the brain stereotaxic atlas, locate the position of posterior limb of right internal capsule (P₁, R& H₁). An operation was done to perforate on the anchor point of skull, and then 0.5ml autologous arterial blood was injected into the right internal capsule.3. Pathomorphological observation of brain tissue: 24h after acute internal capsule hemorrhage, take rabbit's brain and observe changes of its general dissection, then fix itwith 10% formaldehyde solution. Through HE stain, observe their pathomorphological changes under the light microscope.4. Measurement of spontaneous electrical activity of brain: After anesthetization, rabbits were fixed on the stereotaxis instrument with prone position. According to the brain stereotaxic atlas, locate the position of posterior limb of right internal capsule (Pi, R?, H.i) and the position of recording electrode (P2, R3). An operation was done to perforate on two anchor points of skull, then record spontaneous electrical activity of brain before internal capsule hemorrhage by the recording electrode and RM-6240B biological signal collecting and processing system. Establish internal capsule hemorrhage animal model, and spontaneous electrical activity of brain was recorded respectively during different phase after internal capsule hemorrhage. Changes of the number in slow wave were analyzed for lmin during different phase under internal capsule hemorrhage conditions.5. Measurement of SLSEP: According to foregoing methods, locate the position of posterior limb of right internal capsule (Pi, R6, H_i) and the position of recording electrode (P2, R3). An operation was done to perforate on two anchor points of skull, and then separate the left posterior tibial nerve. Contact stimulating electrode tightly with the posterior tibial nerve and record SLSEP before internal capsule hemorrhage by the recording electrode and RM-6240B biological signal collecting and processing system. Establish internal capsule hemorrhage animal model, and record changes of SLSEP respectively during different phase after internal capsule hemorrhage. Software was used to analyze the IPL of P1-N1 and peak to peak value of N2-Pi-6. Scores of motor function of posterior limb in rabbits: According to Tarlov's standard, motor function of left posterior limb in rabbits was scored before and after internal capsule hemorrhage.7. Statistical analysis: The data were analyzed by SPSS13.0 statistical software. Beforeand after internal capsule hemorrhage, variance analysis with repeated measure and LSD test were used to analyze changes of IPL of P1-N1 and the number in slow wave. Rank-sum test was used to analyze changes of peak to peak value of NrPi: and scores of motor function in posterior limb, a =0.05, two-tailed.;Results1. Pathomorphological observation of brain tissue 24h after internal capsule hemorrhage:(1) Observation through general dissection: The brain volume increased and a large piece of irregular or oval hematoma was confirmed in the posterior limb of right internal capsule.(2) Examination under the light microscope: There were a great deal degenerative and necrotic red blood cells in hematoma. Irregular hemorrhagic focus, punctate hemorrhage, inflammatory cell infiltration and angiotelectasis were detected in brain tissue around hematoma. Brain tissue next to hemorrhagic focus showed looseness and edema and there were necrotic nerve cells and glial cells.2. Under this experiment condition, the number of slow wave increased significantly during different phase after internal capsule hemorrhage, compared with before hemorrhage (P<0.01).3. Under this experiment condition, IPL of Pi-Ni prolonged significantly (P<0.01) and peak to peak value of N2-P1 decreased significantly (P<0.01) during differer* phase after internal capsule hemorrhage, compared with before hemorrhage.4. Scores of motor function in posterior limb: After acute internal capsule hemorrhage, scores of motor function in left posterior limb of rabbits decreased significantly (P<0.05).Conclusions1. Acute internal capsule hemorrhage animal model could be duplicated successfully by stereotaxy and injecting autoblood into internal capsule.2. After acute internal capsule hemorrhage, hemorrhagic stimuli or hematoma compression inhibited excitability of brain cells, thus the component of slow wave increased.3. After acute internal capsule hemorrhage, hematoma compressed ascending sensory nerve fiber and hindered conduction of nervous impulse, so central conduction time prolonged and IPL of Pi-Ni prolonged, conduction velocity of nervous impulse slowed down. IPL of Pi-Ni can reflect central conduction time, thereby, can reflect conduction velocity of central nerve.4. Wave amplitude of SLSEP can reflect excitability of nerve cells. After acute internal capsule hemorrhage, hemorrhagic stimuli or hematoma compression inhibited excitability of nerve cells, therefore, peak to peak value of N2-P1 decreased.5. After acute internal capsule hemorrhage, occupation effect of hematoma caused intracranial hypertension, which affected function of nerve cells and hindered conduction of nervous impulse. Thus, IPL of P1-N1 prolonged, conduction velocity of central nerve and peak to peak value of N2-P1 decreased.6. After internal capsule hemorrhage, hematoma compressed descending motor nerve fiber, the motor function of limbs opposite to hemorrhage was damaged.