甲状旁腺激素及其动员的内源性骨髓干细胞对缺血性脑卒中的作用

Cerebral ischemia is a serious threat to human's life and health, leading to huge burdens to patients' family and the society emotionally and economically. Based on recent progress in stem cell stroke therapy using bone marrow stemc cells (BMSCs) and the recognization on several limitations of transplantation of exogenous BMSCs, the proposed investigation will explore an innovative therapeutic strategy of mobilizing endogenous BMSCs from the bone marrow by using parathyroid hormone (PTH) that has recently shown the effect of BMSC mobilization and repair of ischemic cardiomyocites. In addition to its physiological function of regulating the balance of blood calcium and phosphorus, PTH has been shown to mobilze release of BMSC from the bone marrow into the circulation and promote homing to the ischemic heart via increased SDF-1 level. However, whether PTH-mobilized BMSCs can be used for the treatment of cerebral ischemic stroke has not been reported. In a focal ischemic stroke model of mice, we will demonstrate PTH mobilization of BMSCs from the bone marrow and test PTH promoted regenerative activites in the SVZ. We will focus on neuronal protection and neurovascular repair as well as functional recovery after ischemic stroke. This investigation will provide experimental evidence for a new stroke therapy using PTH and mobilzed endogenous BMSCs.

缺血性脑卒中严重威胁着人类的生命及生活质量。基于骨髓干细胞（BMSCs）移植治疗脑卒中的应用前景和诸多不足，本课题将探讨加速动员内源性BMSCs的释放对治疗缺血性脑卒中的作用。甲状旁腺激素（PTH）为生理性激素，近期实验证实冠状动脉阻塞后，PTH可动员BMSCs至外周血，并通过上调病灶区SDF-1的表达，定向诱导干细胞"归巢"至损伤部位进而改善心肌功能。但PTH对缺血性脑卒中的作用尚未见报道。我们的初步实验结果提示，局灶性脑缺血后PTH可动员骨髓干细胞至外周血，改善缺血灶周围血流，促进神经血管再生。课题组将进一步检测PTH在小鼠皮质局灶性脑缺血后各种BMSCs以及脑内源性干细胞的动员、增殖和"归巢"作用，同时以血管神经网络为着眼点观察缺血灶及其周围血管、神经再生以及神经功能恢复情况，旨在为缺血性脑卒中寻找新的治疗途径。

缺血性脑卒中严重威胁着人类的生命及生活质量。而针对缺血性脑卒中的治疗手段非常有限。干细胞移植治疗对于缺血性脑血管病的治疗具有良好的前景。基于骨髓干细胞(BMSCs)移植治疗脑卒中的诸多局限性,本课题将探讨加速动员内源性BMSCs的释放对治疗缺血性脑卒中的作用。动员内源性的干细胞治疗各种疾病逐渐引起学术界的重视。甲状旁腺激素(PTH)为生理性激素,近期实验证实冠状动脉阻塞后,PTH可动员BMSCs至外周血,并通过上调病灶区SDF-1的表达,定向诱导干细胞"归巢"至损伤部位 进而改善心肌功能。关于PTH对于小鼠的局灶性脑缺血后的作用的研究目前尚无他人报道。本研究以小鼠大脑中动脉皮质支结扎方法建立局灶性脑缺血模型, 给予连续腹腔注射甲状旁腺激素80ug/KG 5天，应用流式细胞术观察缺血后PTH动员骨髓干细胞的表达特点，荧光免疫重染的方法检测PTH治疗对于缺血灶的血管再生及神经再生作用。同时蛋白印记方法检测缺血灶周围VEGF, EPO receptor (EPOR), Ang-1, Tie-1,Flk-1, BDNF 和SDF-1等神经血管生长因子蛋白的表达情况，同时通过贴纸粘附实验检测PTH对于缺血性卒中后小鼠的神经功能修复情况。研究结果提示PTH能显著动员内源性内皮祖细胞的表达，可以促进局灶性脑缺血后血管新生及神经再生过程，并参与了神经功能缺损的修复。本研究旨在为缺血性脑卒中寻找新的治疗途径。