脑损伤过程中血脑屏障通透性的变化及其调节机制

血脑屏障是由脑微血管内皮细胞、星形神经胶质细胞、外膜细胞、血管周围巨噬细胞和基底膜组成的一个复杂系统，对维持中枢神经系统的正常功能非常重要。脑损伤如脑缺血、脑缺氧、脑外伤和蛛网膜下腔出血过程中伴随血脑屏障通透性的变化。脑缺血及其再灌注后可通过花生四烯酸代谢途径、嘌呤核苷酸代谢途径及一氧化氮途径产生自由基，可能是血脑屏障通透性增加的重要机制。血脑屏障的破坏可加重脑损伤程度；脑血管疾病时，保护血脑屏障的完整性可能是减轻脑损伤的重要措施。

Permeability alteration of blood brain barrier and its mechanisms in brain injury

Blood brain barrier (BBB), which is formed by a complex system of cerebral microvascular endothelial cells, astroglia, pericytes, perivascular macrophages, and a basal lamina, plays an important role in maintaining the normal functions of the central nervous system. An increase of permeability of BBB was observed after cerebral ischemia, cerebral hypoxia, traumatic brain injury and subarachnoid hemorrhage. Free radicals were produced in the process of arachidonic acid metabolism, adenosine purine nucleotide metabolism and nitric oxide pathway after cerebral ischemia and reperfusion, which may be an important mechanism of BBB permeability alteration. BBB impairment may aggravate the severity of brain damage, indicating that it is an important therapeutic measurement to maintain the integrity of BBB in reducing brain injury after cerebral vascular diseases.