家兔脑损伤后经颈动脉注射地塞米松对血清髓鞘碱性蛋白的影响

Effects of dexamethasone by carotid injection on serum myelin basic protein after brain trauma of rabbits

目的 :体液髓鞘碱性蛋白 (myelinbasicprotein ,MBP)是急性脑损害的特异性生化指标 ,可标志脑病理程度。本研究通过MBP变化来观察经颈动脉途径注射地塞米松对家兔脑损伤的治疗作用。方法 :3 0只家兔分为A、B、C 3组 ,每组 10只。A组 :经颈动脉注射地塞米松 ;B组 :注射生理盐水 ;C组 :仅行颈动脉显露 ,不作注射。以血清MBP作为观察指标。采用骨窗成形后硬膜外打击法造成家兔脑挫裂伤模型 (右半球 )。致伤前测定血清MBP作为正常对照值。致伤后解剖、显露右颈总及颈内动脉。A组穿刺颈内动脉后注射 0 5mg/kg地塞米松稀释液 ,每 2 4h 1次 ,共 3次 ;B组同样方法注射等量生理盐水 ;C组仅作颈内动脉显露。 72h后取 3组动物血清MBP测定 ,并行统计学分析。结果 :家兔血清MBP正常值为 ( 1 61± 0 68) μg/L。致伤后 72h ,A、B、C 3组动物血清MBP平均值分别为 ( 3 2 5± 1 12 ) μg/L ,( 5 95± 2 0 5 ) μg/L和 ( 5 78± 1 75 ) μg/L ,均较正常值为高 (P <0 0 5 )。但A组和B、C 2组比较 ,血清MBP较低 (P <0 0 5 ) ,而B、C 2组比较差异不显著 (P >0 0 5 )。结论 :兔脑挫裂伤后血清MBP明显升高 ,经颈动脉注射地塞米松后可降低血清MBP 。

Aim:The experiment was conducted to observe the role of dexamethasone by carotid injection after brain injury according to the change of myelin basic protein (MBP).Methods: Experimental model was made by frontoparietal bone windowplasty with extradural hitting on right hemisphere,MBP were detected in 30 rabbits which were divided to 3 groups,each one including 10 rabbits:Groups A(treated with dexamethasone,0.5ml/kg,once per 24h,totally 3 times),B(treated with normal saline,as former method) and C (only exposing carotid but injected nothing).The levels of MBP in 3 groups were regarded as normal value before injury and determined 72h later after injury.Results: The normal level of serum MBP was (1.61±0.68)μg/L,while 72h later,Groups A、B and C were (3.25±1.12)μg/L,(5.95±2.05)μg/L,(5.78±1.75)μg/L,respectively.The values of MBP in 3 groups after injury were higher than those before injury ( P <0.05),but MBP in Group A was much lower than in Group B and C ( P <0.05),there was not a significant difference in MBP between Groups B and C ( P >0.05). Conclusions: MBP obviously increase after cerebral contusion and could decrease by carotid injection of dexamethasone.Therefore,MBP may be a sensitive indicator to assess the degree of injury and the curative effect.