创伤性脑损伤活体脑片不同时相的脂质过氧化损伤

The Phasic Variations of Lipid Peroxidation Damage in Living Brain Slices after Traumatic Brain Injury

目的观测创伤性脑损伤后不同时间大鼠脑组织的脂质过氧化损伤。方法70只SD大鼠随机分为假损伤组(n=10)和脑损伤组,损伤组按伤后1、6、24、48、72和168h观察时间点分为6个亚组(n=10)。用Feeney氏自由落体撞击法制作重型颅脑损伤模型。利用激光扫描共聚焦显微镜观察损伤后不同时间荧光探剂2,7-二氯氢化荧光素(H2DCFDA)与碘化丙啶(PI)标记的活体脑片细胞内脂质过氧化物的动态变化和细胞死亡程度。结果①1、6、24h损伤组脂质过氧化物明显增加(P<0.05),48h达到峰值,之后下降,72h已显著下降(P<0.05),168h恢复正常水平。②1、6h损伤组神经细胞死亡明显增加(P<0.05),24h达到峰值,之后维持不变,24、48、72及168h各损伤组之间细胞死亡无明显差异(P>0.05)。③脂质过氧化物引起神经细胞死亡。结论创伤性脑损伤早期(<72h)脑组织即发生脂质过氧化反应引起神经细胞死亡,并且将持续一周。脂质过氧化物在创伤性脑损伤的继发损害中起重要作用。

Objective To study the time course of lipid peroxidation in the brain after traumatic brain injury. Methods Seventy sprague-dawley（SD） rats were randomly divided into sham-injury groups （n=10） and brain injury groups. The brain injury group was divided into six subgroups according to 1, 6, 24, 48, 72, 168 h after traumatic brain injury （n=10）. Rat model with contusion and laceration of brain was established by Feeney＇s impact with free falling weight. Intracellular lipid peroxide and dying neuronal cell in living brain slice were labeled by fluorescent dyestuff 2,7-dicholorofrescin diacetate （H2DCFDA） and proidium iodide （PI）. The dynamic change of intracellular lipid peroxide and dying neuronal cell in living brain slice were measured by confocal laser scanning microscopy in different times. Results The lipid peroxide of brain injury groups was significantly （P〈0.05） increased in 1 h, 6 h and 24 h after injury, reached its climax at 48 h, then declined, significantly （P〈0.05） decreased at 72 h, and recovered normal level at 168 h. The dying neuronal cell of brain injury groups significantly （P〈0.05） increased in 1 h and 6 h, reached its climax at 24 h, then maintained. There were not significantly （P〉0.05） differences among 24 h, 48 h, 72 h and 168 h. Lipid peroxide could induce neuronal cell death. Conclusion Lipid peroxidation induces neuronal cell death in early（〈72 h） phase after traumatic brain injury, which would maintain a week. Lipid peroxide may play a role in secondary damage after traumatic brain injury.