骨髓基质干细胞加重糖尿病脑缺血损伤的新机制-RAGE介导的信号通路

Diabetic patients have a higher risk of ischemic stroke and poorer outcomes after ischemic stroke. Therefore, development of effective therapies for ischemic stroke in diabetic patients is crucial. Transplantation of bone marrow stromal cells (BMSCs) can improve functional recovery after ischemic stroke in rats without diabetes. However, our previous data have indicated that BMSCs treatment initiated 24 after ischemic stroke in diabetic rats increases vascular damage and fails to improve functional outcomes, the mechanisms by which bone marrow stromal cells based treatment increases vascular damage and fails to improve functional outcomes remains unclear. .The poorer outcomes after ischemic stroke in diabetic rats has been attributed to activation of the receptor for advanced glycation endproducts (RAGE) mediated signal pathway in the ischemic penumbra. Based on the above data, we made the assumption that the adverse effects of BMSCs treatment of stroke in diabetic rats may be attributed to further activation of a RAGE-dependent signal pathway. So we chose to focus on this pathway for our investigation, and we intend to clarify the possible mechanisms by which BMSCs treatment increases vascular damage and fails to improve the outcomes after ischemic stroke in diabetic rats. This study may offer new ideas for using BMSCs to effectively treat diabetes who have suffered from a stroke.

糖尿病患者缺血性脑血管病的发病率、致残率和死亡率均远高于正常人群，亟需探寻有效防治措施。我们的前期研究发现骨髓基质干细胞在治疗糖尿病脑缺血再灌注损伤时，与其在治疗非糖尿病缺血性脑血管病的情形相反，不仅不能改善神经功能的恢复，反而会加重血管损伤，造成以上结果的具体机制目前尚不清楚。.由于晚期糖基化终产物受体介导的炎症反应在脑损伤局部的激活是糖尿病脑缺血再灌注损伤后预后差的重要原因，我们假设：骨髓基质干细胞加重糖尿病脑缺血再灌注损伤的原因可能与进一步激活晚期糖基化终产物受体介导的炎症反应有关。本实验拟以晚期糖基化终产物受体介导的炎症反应通路为切入点，从整体、细胞和分子水平阐明骨髓基质干细胞加重糖尿病脑缺血再灌注损伤的分子机制，为骨髓基质干细胞在临床，特别是在糖尿病脑血管病中有效安全应用提供新思路。

糖尿病患者缺血性脑血管病的发病率、致残率和死亡率均远高于正常人群，亟需探寻有效防治措施。我们的前期研究发现骨髓基质干细胞(Bone Marrow Stromal Cells, BMSCs)在治疗1型糖尿病（type 1 diabetes mellitus, T1DM）大鼠脑缺血再灌注损伤时，与其在治疗非糖尿病缺血性脑血管病的情形相反，不仅不能改善神经功能的恢复，反而会加重血管损伤，造成以上结果的具体机制目前尚不清楚。本研究应用链脲佐菌素对成年雄性SD大鼠进行T1DM造模，诱导14天后进行大脑中动脉缺血再灌注损伤模型制备。术后 24 小时，按不同组别分别相应经尾静脉给予BMSCs悬液 1 毫升（5x106/ml）、甘草酸（Glycyrrhizin，Gly）1毫升（4mg/kg）。实验大鼠随机分4组：1型糖尿病大鼠脑缺血再灌注损伤对照组、 1型糖尿病大鼠脑缺血再灌注损伤BMSCs治疗组、1型糖尿病大鼠脑缺血再灌注损伤Gly拮抗组、1型糖尿病大鼠脑缺血再灌注损伤BMSCs+Gly组。术后 1d、7d、14d，分别对各组大鼠进行神经功能损伤评估。术后5d，应用免疫印迹检测各组大鼠脑缺血半暗带区高迁移率族蛋白B1（high mobility group box 1, HMGB1）和晚期糖基化终产物受体（receptor for advanced glycation endproducts, RAGE）表达情况；术后14d，应用免疫荧光染色，检测各组大鼠缺血区HMGB1和RAGE蛋白表达情况，观察治疗组移植的干细胞在缺血区的聚集情况。研究首次发现：①BMSCs治疗脑缺血再灌注损伤的T1DM大鼠后脑梗死周边区HMGB1和RAGE表达明显升高；②BMSCs治疗脑缺血再灌注损伤的T1DM大鼠加重梗死后神经功能损伤；③应用HMGB1抑制剂甘草酸（Glycyrrhizin, Gly）和BMSCs联合治疗能够减轻T1DM大鼠脑缺血再灌注损伤后神经功能损伤；④应用HMGB1抑制剂Gly和BMSCs联合治疗能降低T1DM脑缺血再灌注损伤后梗死周边区HMGB1和RAGE的表达。研究结果提示HMGB1-RAGE通路可能在BMSCs加重T1DM脑缺血再灌注损伤大鼠的神经功能损伤起重要作用，为BMSCs在临床，特别是在糖尿病脑血管病中有效安全应用提供新靶点。