大鼠局灶性脑缺血再灌注DNA损伤原位检测

目的 研究大鼠大脑中动脉缺血再灌注时，DNA损伤随再灌注时程在各脑区的动态分布情况。方法 用线栓闭合大鼠大脑中动脉30min，然后分别再灌注30min、1h、2h、4h、6h、12h、24h和48h。采用原位PANG（DNA聚合酶I介导的生物素标记的dATP缺口平移)及原位TUENL(末端脱氧核苷酸转移酶介导的dUTP末端标记)分别检测DNA损伤的单链断裂(SSBs)及双链断裂(DSBs)，分别观察SSBs细胞和DSBs细胞在大鼠前囟水平冠状切面的脑组织切片各区域的分布。结果 DNA单链断裂和双链断裂都首先发生在尾壳核(CPU)，而且在再灌注的各时间点，分布在尾壳核和梨状皮质(PI)的PANT或TUNEL阳性细胞数量显著多于分布在额叶皮质(FR)及顶叶皮质(PA)的数量(P＜0．05)。DNA单链断裂比双链断裂发生要早。结论 尾壳核和梨状皮质是受缺血影响的中心区域，额叶和顶叶皮质是受缺血影响相对较轻的区域，可能是缺血半影区。

In situ detection of DNA strand breaks in rat brain after transient focal ischemia

Objective To investigate the distribution of DNA strand breaks with the time points of recirculation in various regions of coronal levels of bregma in rat on the condition of reperfusion after temporal occlusion of middle cerebral artery (MCA).Methods The animal model was created with a monofilament nylon suture blocking the MCA 30 minutes followed by reperfusion of 30 min, 1 h, 2 h, 4 h, 6 h, 12 h, 24 h and 48 h respectively DNA single-stand breaks (SSBs) was detected by in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and DNA double strand breaks (DSBs) was detected by in situ terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL).Results SSBs and DSBs initially occur in caudate putamen (CPU), the number of SSBs-containing cells or DSBs-containing cells in piriform cortex (PI) and caudate putamen is greater than that of frontoparietal cortex (FR and PA) (P< 0.05).Conclusions CPU and PI are at the ischemic core and FR and PA are the penumbra in this animal model.