高压氧对新生大鼠缺氧缺血脑损伤模型脑组织神经细胞凋亡及超氧化物歧化酶和脂质过氧化物的影响

目的探讨高压氧(HBO)对新生大鼠缺氧缺血性脑损伤(HIBD)模型脑组织神经细胞凋亡和超氧化物歧化酶(SOD)、脂质过氧化物(MDA)的影响。方法新生7d龄健康SD大鼠随机分为4组:空白对照组(n=68),假手术组(分离左颈总动脉后不结扎直接缝合皮肤,n=66),HIBD组(模型制作采用经典的Rice法,n=60),HBO组(HIBD后行HBO治疗,1h/次/d,最长治疗7d,n=66)。TUNEL试剂盒检测脑组织凋亡的神经细胞,黄嘌呤氧化酶法测定SOD活力(nU/ml)和化学比色法测定MDA含量(μmol/L)。结果(1)缺氧缺血后不同时间HIBD组皮质和海马神经细胞凋亡明显增多,24h达高峰后逐渐下降;HBO组凋亡细胞数较HIBD组明显减少,但仍较空白对照组和假手术组高,差异有统计学意义(P<0.05);(2)缺氧缺血后HIBD组SOD含量下降,HBO治疗后SOD的含量较HIBD组升高,且随着治疗时间的延长SOD的水平逐渐升高,24h达高峰,然后逐渐下降,各组比较差异有统计学意义(P<0.05);(3)缺氧缺血后HIBD组MDA含量明显升高,18至24h达高峰,随着时间的推移逐渐下降;HBO治疗后MDA含量较HIBD组明显降低,差异有统计学意义(P<0.05)。结论HBO治疗可减轻HIBD后神经细胞凋亡,机制可能与HBO诱导脑组织SOD的表达,增强组织的抗氧化应激损伤有关。

Effects of hyperbaric oxygen therapy on neuron apoptosis and brain SOD and MDA production in hypoxic-ischemic brain injury of neonatal rats

Objective To inquire the effect of hyperbaric oxygen (HBO) therapy on neuron apoptosis and brain production of SOD and MDA in neonatal hypoxic-ischemic brain damage(HIBD) rat model. Methods According to the random serial number, 7 days old SD rats weighting 12~14 g were divided into four groups: normal control group (n=68), sham operated group (n=66), HIBD group (n=60, classic Rice's method) and HBO group (n=66, after HIBD, receiving HBO therapy 1 h once a day for 7days). Neuron apoptosis was tested by TUNEL kit. The SOD and MDA were measured by the methods of xanthinoxidase and chemical colorimetriy. Results The positive cells of apoptosis on cortex and hippocampus in HIBD group increased significantly after ischemia-hypoxia at different time, peak appeared at 24 hours and then decreased along with the time going. The positive cells of apoptosis in HBO group dropped obviously compared with HIBD group, but still higher than normal control and sham operated group (P<0.05). The SOD level in HIBD group were lower. After HBO exposure, the SOD level rose significantly and continuously, peak reached at 24 hours and then decreased compared with HIBD group (P<0.05). The MDA level in HIBD group increased, peak happened at 18 to 24 hours and then reduced along with time. HBO exposure decreased the MDA level compared with HIBD group (P<0.05). Conclusions Compared with those of HIBD group, HBO may induce the expression of SOD, decreased the level of MDA and reduced the apoptosis of neurons.