高压氧对新生大鼠缺氧缺血性脑损伤后在体神经干细胞的影响

目的： 新生鼠的神经生发区-室管膜下区（SVZ） 和海马齿状回（DG）聚集了多种不同发育阶段神经干细胞（NSCs），它们可分化产生新的神经元和胶质细胞。本研究探讨缺氧缺血性脑损伤（HIBD）对脑生发区NSCs的损伤及高压氧（HBO）对此损伤的影响。从在体NSCs 探讨HBO对新生大鼠HIBD的保护作用机制。 方法： 新生7 d龄SD大鼠随机分为4组：① 正常对照组（CON，n=16）；② HIBD 模型组（HIBD，n=16）；③ 高压空气组（HBA，n=16）；④HBO治疗组（n=16）。Rice法复制HIBD模型，并予HBA或HBO治疗，每天1次共7 d。BrdU免疫组化显示在体NSCs。并取损伤侧脑SVZ区组织，体外NSCs培养并进行神经干细胞球计数。 结果： HIBD组生发区在体BrdU 阳性细胞和体外培养的神经干细胞球数目明显少于对照组。HBO组SVZ区的BrdU阳性细胞增多；体外培养的神经干细胞球增多。HBA组增加不明显。 结论： 新生大鼠HIBD后生发区NSCs减少，HBO治疗可以减轻HIBD后NSCs的死亡。HBA治疗无明显作用。

Effect of hyperbaric oxygen on NSCs in the neonatal rat with hypoxic-ischemic brain damage

AIM: To discuss the mechanism of hyperbaric oxygen (HBO) therapy by assessing the changes of neural stem cells (NSCs), after hypoxic-ischemic brain damage (HIBD) in neonatal rats. METHODS: Seven-day-old SD rat pups were randomly divided into 4 groups: control group (CON, n=16), HIBD group (n=16), hyperbaric air group (HBA, n=16), and HBO group (n=16). The HIBD model was produced by permanent occlusion of left common carotid artery and was exposed to a mixture of 8% oxygen and 92% nitrogen for 2 h (at 37 ℃). HBA and HBO treatment was administered by placing pups in a chamber (2 ATA for 1 h) 1 h after hypoxia exposure and performed once daily for 7 days. BrdU immunohistochemistry was used to assess how the insult had affected NSCs in the SVZ of the lateral ventricle and DG of the hippocampus. The NSCs from the ipsilateral SVZs were isolated at 3 weeks recovery from hypoxia-ischemia (HI). The number of spheres was then counted as an index of the number of NSCs residing within the SVZ. RESULTS: At 3 week survival, the SVZ of HIBD group was smaller and markedly less cellular than control group. BrdU-positive cells were dramatically decreased in the SVZ and DG of the affected hemisphere (P<0.01) and by in vitro cell culture it contained less NSCs in the SVZ of the affected hemisphere, too. HBO resulted in weaker proliferation of BrdU-positive cells in the SVZ and DG. CONCLUSION: Hypoxia-ischemia depletes the rat NSCs in SVZ and DG, HBO can weak this depletion, but HBA has no effect.