激光调控内源性神经干细胞的增殖分化及脑功能重建

背景: 大量研究表明增强脑内源性神经细胞的增殖能力和自我修复将成为治愈缺血缺氧性脑损伤有价值的方法之一.目的:观察氦氖激光对新生大鼠缺血缺氧性脑损伤内源性神经干细胞增殖分化及脑功能重建的影响.方法:7 d龄健康Wistar新生大鼠,建立缺血缺氧性脑损伤模型后第2天开始,激光穴位照射组给予氦氖激光照射.穴位选取顶骨正中的"百会"穴,以及第7颈椎与第1胸椎间、背部正中的"大椎"穴.假手术组和模型组不给予激光照射.于第2疗程结束后,用Y-型迷宫检测各组大鼠的学习记忆能力.随后制备脑海马切片,分别进行巢蛋白和微管关联蛋白2免疫组织化学染色.结果与结论:①激光穴位照射组大鼠的学习和记忆能力明显高于模型组(P < 0.05),但与假手术组相比,无明显差异(P > 0.05).②大鼠内源性神经干细胞的表达:与假手术组比较,模型组、激光治疗组齿状回内巢蛋白免疫阳性细胞均明显增多(P < 0.05),且激光治疗组增多幅度大于模型组(P < 0.05).③神经元特有结构蛋白的表达:激光治疗组大脑皮质微管关联蛋白2表达相当广泛,强阳性染成棕褐色的树突呈条索样、流星样放射状分布,海马各区锥体神经元和齿状回颗粒细胞层神经元排列比较整齐,树突连续阳性染色呈树枝状交叉分布于分子层.假手术组与激光治疗组染色所见无明显差别.模型组微管关联蛋白2表达明显减弱.结果提示激光治疗能够促进缺血缺氧性脑损伤新生大鼠脑内源性神经干细胞增殖,诱导其向神经元方向分化,并达到学习记忆功能的重建.

Proliferation and differentiation of endogenous neural stem cells and brain functional reconstruction following laser irradiation

BACKGROUND: Numerous studies have shown that the increase of reproductive activity and self-repair capacity of brain endogenous neural cells might be a valuable method to treat ischemia-hypoxia brain damage. OBJECTIVE: To study the effects of He-Ne laser irradiation on the proliferation and differentiation of endogenous neural stem cells and brain functional reconstruction in newborn rats with hypoxia-ischemia brain damage.METHODS: Newborn rats aged 7 days were prepared for hypoxia-ischemia brain damage models. From the second day of model induction, rats in the laser treatment group were subjected to He-Ne laser irradiation. Acupuncture point included Baihui (DU20) on the median parietal bone, and Dazhui (GV14) between the C7 and T1 and the median back. After the second course, the learning and memory ability of rats were tested by Y-type maze test. Then brain hippocampal sections were made and underwent immunohistochemistry for nestin and microtubule-associated protein-2.RESULTS AND CONCLUSION: In the laser treatment group, the ability of learning and memory were obviously higher than those in the model group (P < 0.05), however, compared with the sham-operated group, the difference was not obviously (P > 0.05). Compared with the sham-operated group, nestin expression in the dentate gyrus was significantly increased in the model and laser treatment groups (P < 0.05), and the increased range was greater in the laser treatment group compared with the model group (P < 0.05). Microtubule-associated protein-2 expression was widely distributed in the cerebral cortex, and darkly stained brown dendrite presented with radiation-shape. Neurons in the hippocampal pyramid and dentate gyrus granular cell layer arranged regularly. Positively stained dendrite presented branch-shape and distributed in the molecular layer. No significant difference was determined between the sham-operated and laser treatment groups. But the microtubule-associated protein-2 expression was significantly weakened in the model group. He-Ne laser irradiation can promote proliferation of endogenous neural stem cells in neonatal rats with hypoxia-ischemia brain damage, induce its differentiation into neurons, thus, achieves reconstruction of learning and memory functions.