Yuan Q, Xie L, Chen C
Guangzhou University of Chinese Medicine, Guangzhou 510800, China.
Department of Encephalopathy, Guangzhou Hospital of Integrated Traditional Chinese and Western Medicine, Guangzhou 510800, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2022 Nov 20;42(11):1705-1711. doi: 10.12122/j.issn.1673-4254.2022.11.15.
To investigate the protective effect of astragalus polysaccharide (APS) against blood-brain barrier in a rat model of middle cerebral artery occlusion (MCAO) and the role of P2X7R channel in the protective mechanism.
In rat microglial cell models of oxygen and glucose deprivation (OGD) or ATP treatment, the formation of blood-brain barrier was assessed using the leak test, and the effect of APS on the permeability of the blood-brain barrier was determined using LC-MS. In 12 SD rats, MCAO model was established followed by treatment with intraperitoneal injection of normal saline (= 6) or APS (45 mg/kg, =6) for 3 consecutive days, with another 6 rats without MCAO receiving saline injections as the control group. The permeability of the blood-brain barrier of the rats was evaluated by determining Evans blue (EB) extravasation, and ATP content in the brain tissue was detected using ELISA; the expression levels of matrix metalloproteinase-9 (MMP-9) and P2X7R in the brain tissue were detected with Western blot.
In the cell model of OGD or ATP treatment, APS treatment obviously promoted the repair of blood-brain barrier integrity. In the rat models, the EB content in the brain tissue and the blood-brain barrier permeability increased significantly in MCAO+saline group and MCAO+APS group as compared with those in the control group ( < 0.01). Compared with saline treatment, APS treatment significantly decreased EB content in the brain tissue and improved the blood-brain barrier permeability in the MCAO rats ( < 0.05). MCAO caused a significant reduction of ATP content and obviously increased the expression levels of MMP-9 and P2X7R in the brain tissue of the rats ( < 0.01), and these changes were significantly alleviated after APS treatment ( < 0.01 or 0.05).
APS can protect the brain tissue of MCAO rats by stabilizing the internal environment, down-regulating the expression of MMP-9 and improving the permeability of blood-brain barrier under cerebral ischemia and hypoxia, and its mechanism may involve the inhibition of P2X7R channel.
探讨黄芪多糖（APS）对大脑中动脉闭塞（MCAO）大鼠模型血脑屏障的保护作用及P2X7R通道在其保护机制中的作用。
在氧糖剥夺（OGD）或ATP处理的大鼠小胶质细胞模型中，采用渗漏试验评估血脑屏障的形成，并用液相色谱-质谱联用（LC-MS）法测定APS对血脑屏障通透性的影响。将12只SD大鼠建立MCAO模型，然后连续3天腹腔注射生理盐水（n = 6）或APS（45 mg/kg，n = 6）进行治疗，另取6只未行MCAO的大鼠注射生理盐水作为对照组。通过测定伊文思蓝（EB）外渗评估大鼠血脑屏障的通透性，用酶联免疫吸附测定（ELISA）法检测脑组织中的ATP含量；用蛋白质免疫印迹法检测脑组织中基质金属蛋白酶-9（MMP-9）和P2X7R的表达水平。
在OGD或ATP处理的细胞模型中，APS处理明显促进了血脑屏障完整性的修复。在大鼠模型中，与对照组相比，MCAO+生理盐水组和MCAO+APS组脑组织中的EB含量和血脑屏障通透性显著增加（P < 0.01）。与生理盐水处理相比，APS处理显著降低了MCAO大鼠脑组织中的EB含量并改善了血脑屏障通透性（P < 0.05）。MCAO导致大鼠脑组织中ATP含量显著降低，MMP-9和P2X7R的表达水平明显升高（P < 0.01），APS处理后这些变化得到显著缓解（P < 0.01或0.05）。
APS可通过稳定内环境、下调MMP-9的表达及改善脑缺血缺氧时血脑屏障的通透性来保护MCAO大鼠的脑组织，其机制可能涉及对P2X7R通道的抑制。
