吸烟对大鼠局灶性脑缺血半暗带内细胞凋亡及Fos蛋白表达的影响

Effects of Smoking on Cell Apoptosis and Expression Level of Fos Protein in Rat Brain Ischemic Penumbra

目的探讨吸烟对脑缺血半暗带内细胞凋亡和Fos蛋白表达的影响。方法雄性Wistar大鼠48只,随机分为假手术组、吸烟组、缺血组、吸烟+缺血组,每组12只。吸烟组和吸烟+缺血组大鼠连续吸烟12周,吸烟量为20支/d。假手术组、缺血组大鼠不吸烟。12周后,缺血组和吸烟+缺血组大鼠建立大脑中动脉栓塞模型。红四氮唑(TTC)染色确定脑缺血半暗带位置,TUNEL法检测细胞凋亡,免疫组织化学检测Fos蛋白表达水平。结果TTC染色证实缺血半暗带位于大脑矢状裂至外侧裂上1/3的皮质组织。假手术组、吸烟组、缺血组和吸烟+缺血组的凋亡细胞数分别为2.54±0.37、20.65±3.26、17.07±2.92和44.92±4.67。与假手术组相比,吸烟组和缺血组的凋亡细胞数均明显增加(P<0.05)。吸烟+缺血组凋亡细胞数增加更为明显,高于吸烟组和缺血组(P<0.05),吸烟和缺血对于增加脑细胞凋亡表现协同作用(P<0.05)。假手术组仅见大脑皮质个别散在分布的Fos蛋白阳性细胞。与假手术组相比,吸烟组、缺血组和吸烟+缺血组的Fos蛋白阳性细胞数量显著增加,平均灰度值显著降低(P<0.05),吸烟+缺血组上述变化最为显著。结论吸烟增加缺血时脑细胞Fos蛋白表达水平,增加凋亡细胞的数量,加重缺血半暗带脑组织的损伤。

Objective To explore the effects of smoking on cell apoptosis and expression level of Fos protein in brain ischemic penumbra. Methods Forty-eight Wistar rats were randomly divided into 4 groups： false-operation group, smoking group, ischemic group and smoking＋ ischemic group,with 12 tats in each group,respectively. The rats of smoking group and smoking＋ischemic group smoked 20 rami a day for 12 weeks. The rats of false-operation group and ischemie group did not smoke. Middle cerebral artery of isehemic group and smoking＋ischemic group was blocked after 12 week. The location of ischemic penumbra was determined by TTC staining, and apoptosis was detected by TUNEL method. The expression level of Fos protein was determined by immunohistochemistry. Results The location of ischemic penumbra was demonstrated at the top 1/3 of fissura sagittalis to fissura ectolaterahs. The number of apoptosis cells of false-operation group,smoking group, ischemic group and smoking＋ischemic group was 2.54±0.37,20.65±3.26,17.07±2.92,44.92±4.67, respectively. The number of apoptosis cells of smoking group and ischemic group increased compared with that of false-operation group （P 〈 0.05 ）, with the highest in smok- ing＋ischemic group （ P 〈 0.05 ）. Smoking was synergetic with ischemia in promoting cell apoptosis （ P 〈 0.05 ）. Few cells that expressed Fos protein could be seen in brain cortex of false-operation group. Compared with that, cells that expressed Fos protein increased significantly in other three groups, and the value of average grey scale decreased significantly （P 〈 0.05 ）. The change was the most conspicuous in smoking＋ischemic group. Conclusion Smoking may increase the expression level of Fos protein in brain ceils and increase the number of apoptosis cells, which aggravates the injury of brain ischemic penumbra.