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

日本老年人多发脑卒中，降低患者的生活质量。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。再生医学可能会诱导受损神经元的再生，并给我们带来即使在中风后也能恢复功能的希望。采用尼龙线栓法制作大鼠大脑中动脉闭塞模型。第1~2天静脉注射人神经干细胞系(F3)、间充质干细胞系(HB10)和小胶质细胞系(HMO)。移植后7d症状评分明显改善，移植细胞向卒中脑内迁移，3d时卒中边缘带可见各种类型的注射细胞，7d时HB10细胞和HMO细胞已消失。只有F3细胞存活到第14天。TUNEL染色…更多的g表明移植减少了该区域发现的凋亡细胞，这可能意味着移植细胞的神经保护作用。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。用免疫组织化学方法检测F3移植后炎症因子的变化。环氧合酶-2(COX-2)在半影区的巨噬细胞和激活的小胶质细胞中表达降低。内皮细胞中诱导型一氧化氮合酶(INOS)的表达也降低。F3移植可减少卒中区域周围的中性粒细胞浸润，从而抑制炎症反应。在本研究中，我们利用大鼠卒中模型论证了细胞移植促进脑梗塞康复的几种机制。我们还在会议上发表了两年来关于中风的文章。我们正在进行进一步的研究，以了解脑梗塞的机制和细胞再生疗法对神经的保护作用。

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