Regenerative medicine for cerebral infarction: Stem cell transplantation in the rat model of middle cerebral artery occlusion

脑卒中在日本老年人中频繁发生，降低了患者的生活质量。功能恢复是罕见的，因此患者数量的增加是现代社会的主要问题之一。再生医学可以诱导受损神经元的再生，甚至在脑卒中后也能给我们带来功能恢复的希望。采用线栓法制作大鼠大脑中动脉闭塞性脑卒中模型。在第1-2天，静脉内注射人源性神经元细胞系，例如神经干细胞系（F3）、间充质干细胞系（HB 10）和小胶质细胞系（HMO）。移植显著改善了第7天后神经系统严重程度评分评估的症状。移植细胞向脑内迁移，第3天在脑卒中边缘区可见各种类型的细胞，第7天HB 10细胞和HMO细胞已消失。只有F3细胞存活至第14天。TUNEL染色 关于我们 g表明移植减少了在该区域中发现的凋亡细胞，这可能意味着移植细胞的神经保护作用。采用分子生物学方法检测神经营养因子的表达水平。与人源性生长因子相比，大鼠源性神经营养因子如表皮生长因子、胰岛素样生长因子-1和粒细胞集落刺激因子在半影区显著增加。免疫组化法检测F3移植后炎症因子的变化。半暗带区浸润的巨噬细胞和活化的小胶质细胞中环氧合酶-2（考克斯-2）表达减少。诱导型一氧化氮合酶（iNOS）的表达在内皮细胞也减少。F3移植减少了卒中区域周围浸润的中性粒细胞的数量，从而抑制了炎症反应。在本研究中，我们证明了细胞移植诱导脑梗死恢复的几种机制，使用大鼠中风模型。在这两年里，我们还在会议上发表了关于中风的文章。我们正在进一步进行研究，以了解脑梗死的机制和细胞再生疗法的神经保护作用Less

Cerebral stroke frequently occurs in Japanese elderly people and lowers quality of life of the patients. Functional recovery is rarely seen, so the increasing number of the patients is one of the major problems in the modern society. Regenerative medicine may induce the regeneration of disturbed neurons and give us hope for functional recovery even after cerebral stroke. We made a stroke model of middle cerebral artery occlusion in rats with nylon suture method. At Day 1-2, human-derived neuronal cell line, such as neural stem cell line (F3), mesenchymal stem cell line (HB10) and microglial cell line (HMO) was intravenously injected. The transplantation significantly improve the symptom evaluated with the Neurological Severity Score after Day 7. Transplanted cells migrated into the stroked brain; at Day 3, every type of injected cells was seen in stroke border zone area, but at Day 7, HB10 cells and HMO cells already disappeared there. Only F3 cells survived until Day 14. TUNEL stainin … More g indicated that transplantation decreased the apoptotic cells found in the area, which may mean neuroprotection by transplanted cells. Molecular biological analysis was performed to evaluate expressional level of neurotrophic factors. Rat-derived neurotrophic factors such as epidermal growth factor, insulin-like growth factor-1 and granulocyte-colony stimulating factor significantly increased in the penumbra area compared to human-derived growth factors. Inflammatory factors were also investigated with immnohistochemistry after F3 transplantation. Cyclooxygenase-2 (Cox-2) expression was decreased in the infiltrated macrophages and activated microglia in the penumbra area. Iducible nitric oxide synthase (iNOS) expression was also decreased in the endothelial cells. F3 transplantation decreased the number of infiltrated neutrophils around the stroke area, leading to inhibit the inflammatory reaction. In the present study, we demonstrated the several mechanisms why cell transplantation induced recovery from cerebral infarction using rat stroke model. We also presented in the conferences and published the articles about the stroke during the two years. We are further undergoing our study to understand the mechanism of cerebral infarction and neuroprotection by the cell regenerative therapy Less