不同方向外力打击致兔颅脑损伤时血清髓鞘碱性蛋白浓度的变化

背景垂直与水平打击产生的受力不同造成破坏性病变程度是否一致?血液中的髓鞘碱性蛋白含量变化与打击形式是否有关联?目的观察不同方向外力打击致兔颅脑损伤时血清髓鞘碱性蛋白浓度以及脑组织形态学变化.设计随机对照实验.单位一所医学院附属医院的神经外科.材料实验于2003-10/2004-01在沈阳医学院中心实验室完成.选择健康家兔30只,雌雄不拘,随机分为垂直打击组和水平打击组,15只/组.方法将全部家兔麻醉后俯卧位固定于多向颅脑损伤打击器的固定台上.分别抽取每只家兔的耳缘静脉血1 mL,用作受伤前髓鞘碱性蛋白对照.垂直打击组实施垂直打击,打击锤直接垂直撞击于颅顶骨上;水平打击组实施水平打击,打击锤水平撞击于兔头侧方.48 h后按相同方法制备两组血清,用作受伤后髓鞘碱性蛋白对照.最后将两组动物断头处死作病理检查.主要观察指标①打击前后两组血清髓鞘碱性蛋白浓度的变化差异.②两组颅脑损伤后的病理形态变化差异.结果按意向处理分析,30只动物均纳入实验.①两组家兔遭遇打击前髓鞘碱性蛋白浓度无明显差异.遭遇打击48 h后髓鞘碱性蛋白浓度垂直打击组与水平打击组亦无明显差异(P＞0.05);②垂直打击组髓鞘碱性蛋白打击前浓度明显低于打击后浓度(1.68±0.86),(5.25±1.96)μg/L,t=3.226,P＜0.05];水平打击组髓鞘碱性蛋白打击前浓度明显低于打击后浓度(1.70±0.91),(5.73±2.07)μg/L,t=3.080,P＜0.05].③打击后病理形态变化垂直打击组双侧额顶近中线部位出现皮层脑组织内血管扩张充血,深层白质水肿,血管外和细胞外间隙明显扩大;水平打击组动物除双侧额顶近中线部位出现与垂直打击组相似变化外,相同的病理还可见于颅底面,但深层白质的病理形式与前者基本一致.结论垂直或水平方向的外力打击均可造成脑损伤.打击前后髓鞘碱性蛋白浓度和打击后病理形态学表明这两种不同方向的外力打击使实验模型兔颅脑受损程度大致接近.

Changes of serum myelin basic protein levels in response to craniocerebral injury by impact from different directions in rabbits

BACKGROUND: Whether horizontal and vertical impacts cause craniocerebral injury of the same degree, and whether serum myelin basic protein (MBP) changes is associated with the direction of impact have been scarcely addressed in previous studies.OBJECTIVE: To observe the change in the serum MBP levels and morphological changes of the brain tissue rabbits with craniocerebral injury resulting from impacts from different directions.DESIGN: A randomized controlled experiment.SETTING: Department of Neurosurgery of a hospital affiliated to a medical university.MATERIALS: This study was conducted in the Central Laboratory of Shenyang Medical College between October 2003 and January 2004. Totally 30 healthy rabbits of either sex were randomly divided into two equal groups to receive vertical and horizontal impact on the head.METHODS: All the rabbits were anesthetized and fixed in prone position onto a table equipped with a device for inducing impact on the head from different directions. Venous blood of 1 mL was taken from the edge of the ear of each rabbit for detecting MBP before injury. The rabbits in vertical impact group received the impact of a hammer falling directly on the parietal bone of the skull. In the horizontal group, the rabbits were subjected to horizontal impact on the lateral side of the skull. Forty-eight hours after the injury, venous blood were again taken for MBP measurement. The rabbits were then killed for pathological examination of the brain.MAIN OUTCOME MEASURES: Changes in serum MBP and pathomorphology of the brain tissues in the two groups after the impact.RESULTS: ① According to intention to treat analysis, all the 30 animals were involved in the experiment. There was no significant difference in serum MBP levels between the two groups before the impact, nor 48 hours after the impact( P ＞ 0.05). In the vertical impact group, serum MBP levels before the impact was( 1.68 ± 0. 86) μg/L, which was significantly lower than that after the impact (5.25 ± 1.96) μg/L, t = 3. 226, P ＜ 0. 05]. ② In the horizontal strike group, serum MBP also significantly increased from the level of( 1.70 ± 0.91 ) μg/L before impact to(5.73 ± 2.07) μg/L after that( t = 3. 080, P ＜ 0.05) . ③ After the impact, vasodilation and congestion in the cortex near the midline of the bilateral parietal region and edema in the deep layer of the white matter were observed in the vertical impact group, along with significant enlargement of the extravascular and extracellular space. In the horizontal group, similar changes except those near the midline of the bilateral parietal region took place after the impact; the same pathological changes were also observed in the basal plane, with nearly identical pathological changes in the deep layer of the white matter.CONCLUSION: Vertical and horizontal impacts can both result in almost identical brain injuries demonstrated by similar changes in serum MBP and the pathomorphology of the brain tissues after the impacts.