惊厥后大鼠海马神经再生与凋亡的动态变化

Proliferation and Apoptosis of Adult Neural Stem Cell after Status Convulsion in the Adult Rat Hippocampus

探讨惊厥持续状态(status convulsion,SC)后大鼠海马神经再生与凋亡的动态变化。建立成年Wistar鼠30minSC模型,在SC后1天至56天的6个时间点上处死动物,处死前1天均腹腔注射5-溴2-脱氧尿嘧啶核苷(5-bromo-2-deoxyuridine,BrdU);采用免疫组织化学方法动态检测BrdU、nestin的表达,确定神经干细胞增殖水平;双重荧光染色标记nestin/TUNEL,确定新生神经干细胞存活时间。与对照组相比,BrdU阳性细胞数目于SC后第7天在CA1区达增殖高峰,28天降至正常水平;于SC后第28天在齿状回达增殖高峰,56天降至正常水平;在SC后第7天,CA3区有大量的BrdU阳性细胞;BrdU和nestin阳性细胞数目无统计学差异。在SC后的前3天,CA1区新增殖的神经细胞呈TUNEL阳性;齿状回新增殖细胞始终表现TUNEL阴性。上述结果提示:SC后能激活自体神经干细胞原位增殖,并且部分新生细胞向损伤区域迁移。

The objective of this research is to explore the proliferation and apoptosis of adult neural stem cell after status convulsion （SC） in the adult rat hippocampus. Seizures were induced in adult Wistar rats injected with lithium and pilocarpine intraperitoneally and controlled 30 minutes later. Rats were sacrificed at 6 time points （1, 3, 7, 14, 28, 56 days） after SC. Each rat was injected with bromodeoxyuridine （BrdU） intraperitoneally 1 day before killed. The expression of BrdU and neuroepthelial stem cell protein （nestin） were determined by immunohis- tochemistry to mark the proliferation of adult neural stem cell. Double-label immunofluorescence of nestin and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） were used to assess the survival of newly generated progenitor cells. In the normal hippocampus formation, only a small amount of BrdU^＋ and nestin^＋ cells were found in dentate gyrus, not CA1 and CA3 region. One day after SC, the amount of BrdU positive cells began to increase in the CA1 region and dentate gyrus, the former peaked 7 days, began to decrease 14 days after, and reached normal 28 days after, while the latter increased up to 20-fold 14 days after and reached normal at 56 days after SC. A large amount of BrdU positive cells were observed in CA3 region at 7 days following SC. The number of BrdU and nestin positive cells of the same region at the same time point had no statistical significance. TUNEL-positive nuclei were observed in almost all of the nestin positive cells in CA 1 region within the first 3 days after SC, but didn＇t exist in dentate gyrus during the whole experiment process. Taken together, we can purpose that SC stimulates the proliferation of inherent neural stem cells within a certain time window, and part of the newly generated cells appear to migrate from proliferation area into the in juried area.