Proliferation and differentiation of endogenous neural stem cells and brain functional reconstruction following laser irradiation / 中国组织工程研究

ABSTRACT

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.