高压氧预处理对大鼠脑缺血再灌注损伤的保护作用及对其海马BDNF和GDNF基因表达的影响

目的:探讨高压氧预处理(Hyperbaric oxygen preconditioning, HBO-PC)对大鼠脑缺血再灌注损伤的保护作用及对其海马脑源性神经营养因子(brain-derived neurotrophic factor, BDNF)、胶质细胞源性神经营养因子(glialcellline-derivedneurotrophicfactor,GDNF)基因表达的影响。方法:将32只SD雄性大鼠随机分为对照组(Sham组)、高压氧对照组(HBO组)、模型组(MCAO组)、高压氧预处理+模型组(HBO+MCAO组),对HBO组和HBO+MCAO组连续给予高压氧预处理5天,随后对MCAO组和HBO+MCAO组进行右侧颈内动脉栓线术,建立大脑中动脉闭塞(middle cerebral artery occlusion, MCAO)模型,其他两组行假手术,于术后第7天对各组大鼠进行Morris水迷宫行为学检测和神经功能评分,检测结束后处死大鼠,进行神经功能缺损评分及氯化三苯基四氮唑(2,3,5-triphenyltetrazolium chloride, TTC)染色;通过蛋白免疫印迹法(Western Blot)检测大鼠海马组织BDNF和GDNF的基因表达情况。结果:(1)神经功能评分提示:Sham组和HBO组均未出现神经功能障碍,MCAO组大鼠出现明显的神经功能障碍,MCAO+HBO组神经功能评分明显高于MCAO组(P0.05)。(2)TTC检测提示:Sham组和HBO组脑组织损伤一侧均未出现梗死灶,MCAO组出现较大的梗死面积比(25.45±8.75)%,MCAO+HBO组的梗死面积比(18.84±10.55)显著小于MCAO组,差异具有统计学意义(P 0.05)。(3)Western Blot检测显示:MCAO组BDNF与GDNF基因表达水平显著低于Sham组和HBO组,差异具有统计学意义(P 0.05),而MCAO+HBO组可以逆转这一效应,差异具有统计学意义(P 0.05)。结论:高压氧预处理可以通过调节BDNF、GDNF基因表达,改善MCAO模型大鼠神经功能和认知水平,发挥神经保护作用。

Protective Effect of Hyperbaric Oxygen Pretreatment and the Expression of BDNF and GDNF Genes in Hippocampus of Rats after Cerebral Ischemia Reperfusion

ABSTRACT Objective: To investigate the protective effect of hyperbaric oxygen conditioning (HBO - PC) on cerebral ischemia-reperfusion injury in rats and the expression of brain - derived neurotrophic factor (BDNF) and glial cell - derived neurotrophic factor (GDNF) genes. Methods: 32 Sprague-Dawley rats were randomly divided into three groups: control group (sham group), hyperbaric oxygen control group (HBO group), model group (MCAO group), hyperbaric oxygen pretreatment + model group (HBO + MCAO group). HBO group and HBO + MCAO group were given hyperbaric oxygen pretreatment for 5 consecutive days, MCAO group and HBO + MCAO group were given right internal carotid artery embolization to establish middle cerebral artery occlusion (middle cerebral artery occlusion). The other two groups received fake surgery. Morris water maze behavior test and nerve function score were performed on the 7th day after operation. After the test, the rats were killed, the nerve function defect score and 2,3,5-triphenyltetrazolium chloride were performed, the gene expression of BDNF and GDNF in rat hippocampus were detected by Western blotting. Results: (1) the neurological function score showed that there was no neurological dysfunction in sham group and HBO group, and there was significant neurological dysfunction in MCAO group. The neurological function score in MCAO + HBO group was significantly higher than that in MCAO group (P < 0.05). (2) TTC showed that there was no infarct on the injured side of brain tissue in sham group and HBO group, and the ratio of infarct area in MCAO group was (25.45± 8.75)%, and that in MCAO+HBO group was (18.84±10.55) significantly lower than that in MCAO group, the difference was statistically significant (P < 0.05). (3) Western blot showed that the gene expression level of BDNF and GDNF in MCAO group was significantly lower than that in sham group and HBO group, the difference was statistically significant (P < 0.05), but MCAO + HBO group could reverse the effect, the difference was statistically significant (P < 0.05). Conclusion: Hyperbaric oxygen pretreatment can improve the neural function and cognitive by regulating the expression of BDNF and GDNF genes, and play a neuroprotective role of cerebral ischemia-reperfusion.