The Experiment Research Of Propofol Protective Effects On Cerebral Hemorrhage Rats

【Objective】Intracerebral hemorrhage (ICH) is a common and the most devastating type of stroke. The mechanisms of brain injury after ICH are complicated and not fully understood.Treatment is primarily supportive, and outcomes remain poor. It is very significant to find a satisfactory treatment to ICH. The purpose of this research was to study the protective effects and mechanism of propofol on cerebral hemorrhage rats induced by collagenase, and to provide more experimental bases for its clinical use in the future.【Methods】Adult male Sprague-Dawle rats (weight: 250～300g) were randomly divided into four groups including normal group, sham operation group, model group and propofol group. The later three groups were divided into five time points (6h, 12h , 24h, 48h and 96h after operation).According to Rosenberg's method, the intracerebral hemorrhage (ICH) model was established by injecting 0.4U Collagenase VII into right pallida under the direction of stereotaxic apparatus. Sham group underwent intracranial needle placement without. Collagenase infusion. Four hours after ICH models were selected, the rats in propofol group were given intraperitoneal injection with propofol 100mg/kg/d. Normal group, sham operation group and model group were not injected any drugs but Sodium Chloride. At five time points (6h, 12h, 24h, 48h, 96h after operation) all the animals' heads were cut off after the rats' behavior scored. The rats were anaesthetized and perfused at the 6h, 12h, 24h, 48h, and 96h after operation. Routine pathological slices were made, using HE stain to observe hemorrhagic focus and brain edema. We assayed cell apoptosis by TUNEL. The expressions of ICAM-1 in the brain tissue around the homatoma were measured by immunochemistry. In the second experiment, the rats'heads were cut off directly. The expressions of NF-κB in the brain tissue ipsilateral and contralateral of the homatoma were measured by Western blot. Cells' ultrastructures were observed with electromicroscope by uranium-lead double stain.【Results】1. Rat nerve function defect score: According to Bederson's nerve function defect (NFD) score standard, the rats' scores of normal goup and pseudo-operation group were 0; the rats' scores of ICH model group and propofol group were 3; but with time going, the NFD scores in ICH model group and propofol group were descending in different extent; the latter descended faster than the former; there was statistic significance in propofol group compared with the model group at 96h (P＜0.05). 2. Pathologic change: (1) HE staining: The hematoma in brain tissue slices was seen obviously at 6h and 12h in model group; Nerve cells and glial cells swelled, and in cell space there were vacuoles of different sizes and the cell space increased with some inflammatory cells infiltration, which become much more serious at 24h, 48h and 96h, but the phenomena were less lessened in propofol group than in model group. (2) Ultrastructure: Twenty-four hours after ICH, astrocytes became varicose and vacuole obviously, some of which got degeneration and necrosis; neurocytes slightly degenerated into karyopyknosis; chromatin agglomerated and electron density increased; myelin sheath lamella partially ruptured and collapsed; axis-cylinder contents dissolved; capillary vessel endothelium cells swelled and blood brain~ barrier was destroyed. 48h after cerebral hemorrhage, astrocytes were highly swelled and chromatin disappeared; part of cell's membrane collapsed and organells were scattered out of. cells; neurocytes degenerated and cell plasma got vacuole; nuclear membrane was sunken wth chromatin agglutination; mitochondrions were swelled with mitochondrion cristae broken. Myelin sheath lamella ruptured and collapsed; many axions were empty; capillary vessel endothelium cells swelled and the cavity was narrowed; the astrocytes at the cortex layer in hematoma side swelled slightly and endothelium cells were swollen; myelin sheath lamella locally loosened; blood .brain barrier was destroyed; neurocytes were nearly normal; occasionally, some pycnosis neurons were seen; neuron ultrastructures in normal group and pseudo-operation group were normal; the changes of cell ultrastructures were much less in therapy group than those in model group.4. Neuroeyte apoptosis: only few apoptosis cells were seen in normal group and pseudo-operation group; TUNEL stain positive cells near hematoma appeared at 6 h after operation and increased at 24 h and then reached to the highest at 48 h, but displayed decline at 96 h in model group; there was significant difference at each time point (P＜0.01) between model group and normal group or pseudo-operation group. TUNEL stain positive cells in propofol group reduced significantly than model group (P＜0.05) at each time point, especially at 24 h, 48 h and 96h.5. The expression of ICAM-1 No ICAM-1 positive cells appeared in normal group and only some cells near needle path showed ICAM-1 positive in pseudo-operation group; a few cells near hematoma expressed ICAM-1 at 6 h, which increased at 24 h and then reached to the highest at 48 hour but displayed decline at 96 h in model group, but the number of ICAM-1 positive cells was still much more than that of pseudo-operation group (P＜0.01). However, ICAM-1 positive cells in propofol group reduced more significantly at any time pint except for 6 h than model group (P＜0.05).6. The expression of NF-κB Comparing to normal group, the expression of NF-κB in sham group and the contralateral in model group remained the same. In the model group, the NF-κB expression ipsilateral of the homatoma increased at 6h and reached the highest at 24h(P＜0.01),decreased at 48h and continued to 96h(P＜0.05). In the propofol group, the NF-κB expression decreased obviously at 24h and 48h(P＜0.05).【Conclusions】Brain edema and cell apoptosis are the most important pathological changes after ICH. Propofol can effectively reduce edema and cell apoptosis and play a protective role on cerebral hemorrhage indued by collagenase. It may inhibit NF-κB and ICAM-1 expression, reduce inflammatory medium release and cell apoptosis, protect the blood brain barrier. These might be involved in its protective mechanism.