放射线对小鼠海马神经干细胞增生与死亡的影响  

Effect of Irradiation on Neuronal Stem Cell Death and Proliferation in Hippocampus in Mice

作　　者：王胜[1] 张钰[1] 高剑峰[1] 王小阳[1] 朱长连[1] 

机构地区：[1]郑州大学第三附属医院儿科,郑州450052

出　　处：《实用儿科临床杂志》2009年第21期1677-1679,共3页Journal of Applied Clinical Pediatrics

摘　　要：目的探讨放射线对基因突变Harelequin(Hq)小鼠和对应野生型小鼠海马神经细胞发生区的细胞死亡以及新生细胞存活的影响。方法出生60d的Hq和野生型小鼠腹腔注射5-脱氧尿嘧啶核苷(BrdU)2次后予左侧大脑半球照射7Gy,照射组和对照组大鼠分别在照射4h和4周灌注取脑,脑组织切片进行激活的半胱天冬酶、BrdU、Ki67免疫组织化学和HE染色,采用体视学图像分析系统进行阳性细胞计数和面积测定。结果基因突变的Hq小鼠神经元发生区的半胱天冬酶依赖的细胞凋亡多于野生型小鼠,射线照射诱导早期大量的海马齿状回颗粒细胞层及颗粒细胞下层的细胞出现半胱天冬酶依赖的细胞死亡,但Hq小鼠的半胱天冬酶依赖的细胞凋亡明显低于野生型小鼠。2种正常小鼠神经元发生区的细胞增生无明显差异,射线照射后早期存活的新生细胞在Hq小鼠明显低于野生型小鼠,长期存活的新生细胞尽管较对照组显著减少,但2种小鼠之间无明显差异。放射线照射后Ki67阳性细胞均较其对照组减少,其中在Hq小鼠减少最为明显,然而海马颗粒细胞层的总体积在Hq小鼠与野生型小鼠之间以及照射组与对照组之间无明显差异。结论放射损伤对凋亡诱导因子下调的Hq小鼠海马齿状回新生细胞早期死亡和长期增生抑制较野生型明显。射线照射导致Hq小鼠海马颗粒细胞层的新生细胞早期大量死亡并非以半胱天冬酶依赖的凋亡途径为主。Objective To study the effect of irradiation on neuronal stem cell death and proliferation in the neurogenic area of hippocampus in both wild type mice and gene mutation （Harlequin） mice. Methods The postnatal 60 - day mice were injected with （ i. p） BrdU （5 - bronmodexyuridine ） with a dose of 50 mg/kg per day for 2 days before the left brain hemisphere was irradiated with a dose of 7 Gy. The mice were sacrificed either 4 hours or 4 weeks after irradiation. The paraffin embedded serial hippocampus sections were stained with active caspase - 3 for detecting apoptotic cell death, or BrdU and Ki67 for detecting cell proliferation. The positive cells were counted by using stereology microscopy and the area of granular cell layer in dentate gyrus was traced. Results The number of active caspase - 3 positive cells in the dentate gyrus of normal Harlequin mice was higher than that of wild type mice. The number was increased dramatically at 4 hours after irradiation in both wild type mice and Harlequin mice,which was much more pronounced in the wild type mice. Cell proliferation in the normal dentate gyrus was of no difference between wild type and Harlequin mice as indicated by BrdU and Ki67 immunostaining. However,the number of BrdU labeled cells decreased as early as 4 hours after irradiation and became more prominent in the Harlequin mice. The decrease was even more pronounced at 4 weeks after irradiation ,but no difference was found between wild type and Harlequin mice. The number of Ki67 positive cells decreased after irradiation and became more pronounced in Harlequin mice at 4 weeks after irradiation. However, the total volume of dentate gyrus showed no significant change after irradiation for both types of mice. Conclusions Irradiation has more obvious effect in Harlequin mice than that in wild type mice on newborn cell death and stem cell proliferation. The newborn cell death at early phase after irradiation in the Harlequin mutant mice is not mainly through caspase -dependent apoptosis pathway.

关 键 词：凋亡 细胞增生 放射 脑 海马 小鼠 

分 类 号：R739.4[医药卫生—肿瘤]