摘要
目的 预电刺激小脑顶核对大鼠脑缺血 /再灌注后DNA氧化性损伤的保护作用 ,以了解电刺激小脑顶核对实验性脑缺血及再灌注后神经保护的分子机制。方法 健康雄性Wistar大鼠 10 6只 ,体重( 2 5 0± 30 ) g ,随机分为 4组 :( 1)单纯造模组 ;( 2 )预刺激组 ;( 3)毁损小脑顶核组 ;( 4 )假手术组。毁损小脑顶核组大鼠用鹅膏氨酸毁损两侧小脑顶核 ,预刺激组、毁损小脑顶核组大鼠均以电刺激器刺激左侧小脑顶核 ,前 3组大鼠用线栓法成功制作可复流的MCAO模型 2h后再灌注。在再灌注后 6、2 4、4 8h将大鼠断头取脑 ,取第 3片提取DNA或RNA。DNA样品经酶解后上高效液相 电化学检测器检测 8 ohdG。RNA样品通过RT PCR的方法探测rOOG1mRNA的表达。结果 ( 1)大鼠脑缺血 /再灌注后缺血区 8 ohdG堆积。预刺激组再灌注各时点的 8 ohdG含量均较单纯造模组及毁损小脑顶核组减少 (P <0 .0 1) ;( 2 )单纯造模组及毁损小脑顶核组脑缺血 /再灌注后rOGG1的转录水平相似 ,再灌注后 6h其rOGG1mRNA几乎检测不到 ,随时间的延长其转录水平有所增加 ,但仍较假手术组及预刺激组低 (P <0 .0 1)。预刺激组再灌注后 6h其rOGG1mRNA的表达量与假手术组无显著性差异 ,但再灌注后 2 4及 4 8h其rOGG1mRNA的表达量均较假手术组增加 (P <0 .0 1)。
Objective To investigate the molecular mechanisms of fastigial nucleus(FN) electrical stimulation protecting against ischemia reperfusion induced oxidative DNA damage in rat brain. Methods One hundred and six male Wistar rats weighting (250±30)g were assigned into 4 groups: (1) pure model group; (2) fastigial nucleus stimulation group; (3) fastigial nucleus lesion group; (4) sham operated group. The FN of third group was destroyed by ibotemic acid(IBO) 5 days before FN stimulation. The focal cerebral ischemia and reperfusion models were made by thread embolish of middle cerebral artery in all groups except the fourth group. Rats were killed at 6, 24 and 48 hours after ischemia/reperfusion. The brains were removed and sliced into 2 mm sections. The third section was applied to DNA or RNA extraction. DNA was analyzed by HPLC with the electrochemical (EC) detection. Using a semi quantitative reverse transcription polymerase chain reaction assay on total mRNA from the ischemic tissue, OGG1 mRNA was determined in rat brains. Results (1) Oxidative DNA damage product and 8 hydroxy 2′ deoxyguanosine (8 ohdG) were accumulated following ischemia reperfusion in rat brains. The amount of 8 ohdG in FN stimulation group was significantly reduced compared with that of pure model group and FN lesion group ( P < 0.01 ), whereas no significant difference was observed in pure model group and FN lesion group. (2) rOGG1 mRNA expression in pure model group after reperfusion was not different from that in FN lesion group and levels of rOGG1 mRNA at 6 hours after ischemia/reperfusion were very low. At 24 and 48 hours after ischemia/reperfusion rOGG1 mRNA expression increased a little in pure model group and FN lesion group, but there was significant reduction compared with sham operated group and FN stimulation group ( P < 0.01 ). rOGG1 mRNA expression in FN stimulation group at 6 hours after reperfusion was not different from that in sham operated group, but rOGG1 transcript levels at 24 and 48 hours after ischemia/reperfusion increased significantly ( P < 0.01 ). Conclusions (1) Ischemic injury occurs during the reperfusion phase of ischemia reperfusion and these insults may be due to DNA damage. (2) The neuroprotective mechanism of fastigial nucleus electrieal stimulation is associated with upregulation DNA repair enzymatic activity.
出处
《卒中与神经疾病》
2004年第3期147-150,共4页
Stroke and Nervous Diseases
基金
国家自然科学基金资助 (No .3 93 762 61)
关键词
电刺激
小脑顶核
脑缺血/再灌注
DNA氧化性损伤
修复
Electrical stimulation Fastigial nucleus Ischemia/reperfusion DNA oxidative damage Repair
