| Objective: Traumatic brain injury(TBI)accounts for the second place in the systemic injury, but it's morbidity and mortality is in the first one. In China there are about 60 million people who occurred traumatic brain injury each year, of which 10 million people died. With the development of modern traffic, traffic accidents will continue to grow. Improving the cure rate of traumatic brain injury is the responsibility of the medical worker.Analgecine is a non-protein substances isolated from rabbits immunizing with vaccinia virus vaccine, used to be applied in clinical pain and cerebral infarction. Recent studies have shown that Analgecine can protect neurons under hypoxia and promote axonal growth, inhibit the release of bradykinin so as to relieve edema. This study was to investigate the fitness of Analgecine protecting brain under traumatic brain injury(TBI),provide the theoretical basis for clinical application.Methods:1 Grouping and model preparationFifty adult male SD rats (the weight is between 280 and 320 gram) are divided randomly into 5 group, sham-operation group, trauma group ,minidose Analgecine group, mediandose Analgecine group and large dose Analgecine group. Each group is composed of 10 rats. All the rats were anesthetized with intraperitoneal injection of 10% chloral hydrate (350mg/kg). The scalp was listerized with iodine and 75% alcohol and incised on the midline. An atraumatic craniectomy was performed by removing the left parietal bone (3mm posterior to the coronary suture , 3mm lateral to the sagittal) , to form a window about 4.5mm in diameter. Injury was induced by the fluid percussion device, whose pendulum was set at the same height. The rats on the sham-operation group were only removed the parietal bone with no injury. Within thirty minutes after trauma, rats in treatment groups respectively received analgecine 5u/kg, 10u/kg, 20u/kg, which were injected intravenously. The sham-operation and trauma groups were given 5ml normal saline in the same way.2 Neurobehavior evaluationObserve the extent of animal behavior disorder when they were awake from anesthesia, using Bederson method as the score standard. 3 Brain water content and Permeability rate of blood-brain barrier 22 hours after TBI, 6 rats of each groups were injected with 2% evansblue(EB) (3ml/kg), then 2 hours for circulation, the brain was taken out instantly. A part of brain tissue was taken at the forward edge of brain injury focus to determine the water content by the means of the wet-dry weighting method. Take approximately another part of brain tissues behind the injury focus. The optical density (OD) of the EB formamide solution was determined by UV spectrophotometry at 620nm, then get the content of EB (μg) according to the standard curve. Permeability rate of BBB was expressed as EB per gram of wet brain tissue (μg/g).4 Nissl staining72 hours after TBI, the remaining 4 rats in each groups were perfused with 4% paraformaldehyde. The brain were taken out and embedded in paraffin, sliced, observed after Nissl staining.5 Statistical methodsAll data were expressed as mean±standard deviation (X±S). Statistical analysis was carried out with ANOVA or nonparametric rank test by using SPSS 13.0 statistical package. P﹤0.05 was considered significant.Results:1 Neurobehavior evaluation results: The neurobehavioral disorder score of trauma group, minidose Analgecine group, mediandose Analgecine group and largedose Analgecine group were(8.4±1.3)points,(7.1±1.2)points,(6.7±1.3)points,(5.4±1.0)points; the score of Analgecine group was significantly lower than trauma group, and the difference was statistically significant (P<0.05); the score of largedose Analgecine group was lower than minidose and mediandose Analgecine group, and the difference was statistically significant (P<0.05); the score of mediandose Analgecine group was slightly lower than minidose Analgecine group, but the difference was not statistically significant (P>0.05).2 Brain water content and Permeability rate of blood-brain barrier: The brain water content of trauma group, sham-operation group, minidose Analgecine group, mediandose Analgecine group and largedose Analgecine group were (84.23±1.52)%,(77.54±0.53)%,(81.13±1.03)%,(79.47±0.77)%,(78.53±0.76)%; the permeability rate of blood-brain barrier were(44.83±3.27)μg/g,(12.80±1.46)μg/g,(36.27±3.10)μg/g,(31.42±2.94)μg/g,(26.80±2.24)μg/g;compared with sham-operation group, the brain water content and permeability rate of blood-brain barrier of the other four group increased in different degrees; compared with trauma group, the results of Analgecine group was significantly lower, and there was statistical difference (P < 0.05); there was dose-effect relationship.3 Morphology:3.1 Three days after fluid percussion injury, the brain was removed. The brain surface of sham-operation group was normal; there was significant brain contusion kitchen and subdural hematoma in trauma group; the brain contusion kitchen and subdural hematoma of minidose and mediandose Analgecine group decreased, and the ones of largedose Analgecine group was not obvious.3.2 Nissl staining: the nerve cells in hippocampus of sham-operation group arranged in neat rows and had intact cell shape, large round nucleus, prominent nucleolus, a large number of Nissl bodies. The number of nerve cells in injured side of hippocampus decreased, while these cells had the characteristics of nerve cell degeneration, such as nuclear dissolution, nuclear fragmentation, nuclear condensation and disappearance of Nissl bodies, it is common in hippocampus CA1 and CA2 area. Compared with trauma group, the nerve cells in injured side of hippocampus arranged more orderly and had full nucleus, clearer nucleolus, a few scattered nuclei shrinkage, more Nissl bodies.Conclusion:1 Analgecine can significantly improve the neurological behavior and reduce brain edema and inhibit damaging of blood-brain barrier and protect neurons in rats after TBI, therefore Analgecine have a therapeutic effect to TBI.2 Dose effect relationship exist in Analgecine treating rats after TBI.
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