脑源性神经营养因子对脑缺血再灌注损伤的影响

Effect of brain-derived neurotrophic factor on cerebral ischemia-reperfusion injury

目的观察脑源性神经营养因子(BDNF)对脑缺血再灌注损伤的影响。方法45只SD大鼠随机数字表法分为假手术组、模型组和BDNF组,每组15只。假手术组和模型组大鼠经侧脑室注射对照AAV病毒,模型组大鼠经侧脑室注射过表达BDNF AAV病毒,24 d后,模型组和BDNF组大鼠采用大脑中动脉闭塞(MCAO)模型,1 h后恢复血流灌注,假手术组大鼠做手术切口不夹闭中动脉。建模24 h后分析假手术组、模型组和BDNF组大鼠神经功能缺损评分;检测3组大鼠脑组织梗死百分比、炎性因子[白细胞介素(IL)-1β、肿瘤坏死因子-α(TNF-α)和IL-6]、氧化应激指标[谷胱甘肽(GSH)和丙二醛(MDA)]、铁离子水平;采用蛋白质免疫印迹(Western blot)分析3组大鼠脑组织中铁死亡蛋白谷胱甘肽过氧化物酶4(GPX4)的表达水平。组间数据采用单因素方差分析。结果BDNF组神经行为评分[(1.53±0.74)分]明显高于模型组[(3.07±0.80)分],差异有统计学意义(t=5.443,P<0.05)。BDNF组大鼠脑梗死百分比[(22.61±2.89)%]明显高于模型组[(49.91±4.21)%],差异有统计学意义(t=20.700,P<0.05)。BDNF组大鼠脑组织炎性因子IL-6、IL-1β和TNF-α水平[(478.67±32.46)、(47.60±5.52)、(32.27±4.98)pg/ml]明显高于模型组[(925.87±48.90)、(120.73±12.91)、(59.93±6.43)pg/ml],差异有统计学意义(t=29.510、20.170、11.750,P<0.05)。BDNF组大鼠脑组织MDA水平[(2.96±0.14)nmol/mg]明显低于模型组[(3.58±0.22)nmol/mg],差异有统计学意义(t=26.560,P<0.05)。BDNF组大鼠脑组织MDA水平[(9.74±1.32)nmol/mg]明显高于模型组[(6.58±0.53)nmol/mg],差异有统计学意义(t=8.596,P<0.05)。BDNF组大鼠脑组织铁离子水平[(74.33±4.35)pmol/mg]明显低于模型组[(105.93±12.49)pmol/mg],差异有统计学意义(t=9.255,P<0.05)。BDNF组大鼠脑组织GPX4表达水平(1.35±0.12)明显低于模型组(1.96±0.12),差异有统计学意义(t=14.150,P<0.05)。结论BDNF可显著降低炎性因子水平,抑制氧化应激所致得铁死亡,保护神经功能。

Objective To investigate the effect of brain-derived neurotrophic factor(BDNF)on cerebral ischemia-reperfusion injury.Methods A total of 45 SD rats were randomly divided into sham operation group,model group and BDNF group by random number table(15 mice/group).The rats in the sham operation group and model group were injected with control AAV virus through the lateral ventricle.The rats in the model group were injected with BDNF AAV virus through the lateral ventricle.After 24 days,the middle cerebral artery occlusion(MCAO)model was established in the model group and BDNF group.After 1 h,the blood perfusion was restored.The rats in the sham operation group were operated without clamping the middle artery.After 24 h of modeling,the scores of nerve function defects in sham operation group,model group and BDNF group were analyzed.The percentage of cerebral infarction and inflammatory factor[interleukin(IL)-1β,tumor necrosis factor-α(TNF-α)and IL-6],oxidative stress index[glutathione(GSH)and malondialdehyde(MDA)]and iron ion level were analyzed in three groups.The expression level of iron death protein glutathione peroxidase 4(GPX4)in brain tissue of rats in three groups was analyzed by Western blotting.The inter-group data were analyzed by one-way ANOVA.Results The neurobehavioral score of BDNF group[(1.53±0.74)]was significantly higher than that of model group[(3.07±0.80),t=5.443,P<0.05].The percentage of cerebral infarction in BDNF group[(22.61±2.89)%]was significantly lower than that in model group[(49.91±4.21)%,t=20.700,P<0.05].The level of inflammatory factors(IL-6,IL-1βand TNF-α)in brain tissue of rats in BDNF group[(478.67±32.46),(47.60±5.52),(32.27±4.98)pg/ml]was significantly higher than that in the model group[(925.87±48.90),(120.73±12.91),(59.93±6.43)pg/ml,t=29.510,20.170,11.750,P<0.05].The level of MDA in brain tissue of BDNF group[(2.96±0.14)nmol/mg]was significantly lower than that of model group rats[(3.58±0.22)nmol/mg,t=26.560,P<0.05].The level of MDA in brain tissue of BDNF group[(9.74±1.32)nmol/mg]was significantly higher than that of model group[(6.58±0.53)nmol/mg,t=8.596,P<0.05].The level of iron ion in brain tissue of BDNF group[(74.33±4.35)pmol/mg]was significantly lower than that of model group[(105.93±12.49)pmol/mg,t=9.255,P<0.05].The expression level of GPX4 in brain tissue of in BDNF group(1.35±0.12)was significantly lower than that in model group(1.96±0.12,t=14.150,P<0.05).Conclusion BDNF can significantly reduce the level of inflammatory factors,inhibit iron death caused by oxidative stress,and protect nerve function.