The blood–brain barrier (BBB) comprises three cell types: brain capillary endothelial cells (BECs), astrocytes, and pericytes. Abnormal interaction among these cells may induce BBB dysfunction and lead to cerebrovascular diseases. The stroke-prone spontaneously hypertensive rat (SHRSP) harbors a defective BBB, so we designed the present study to examine the role of these three cell types in a functional disorder of the BBB in SHRSP in order to elucidate the role of these cells in the BBB more generally. To this end, we employed a unique in vitro model of BBB, in which various combinations of the cells could be tested. The three types of cells were prepared from both SHRSPs and Wistar Kyoto rats (WKYs). They were then co-cultured in various combinations to construct in vitro BBB models. The barrier function of the models was estimated by measuring transendothelial electrical resistance and the permeability of the endothelial monolayer to sodium fluorescein. The in vitro models revealed that (1) BECs from SHRSPs had an inherent lower barrier function, (2) astrocytes of SHRSPs had an impaired ability to induce barrier function in BECs, although (3) both pericytes and astrocytes of SHRSPs and WKYs could potentiate the barrier function of BECs under co-culture conditions. Furthermore, we found that claudin-5 expression was consistently lower in models that used BECs and/or SHRSP astrocytes. These results suggested that defective interaction among BBB cells—especially BECs and astrocytes—was responsible for a functional disorder of the BBB in SHRSPs.

血脑屏障 (BBB) 包括三种细胞类型：脑毛细血管内皮细胞 (BEC)、星形胶质细胞和周细胞。这些细胞之间的异常相互作用可能导致血脑屏障功能障碍并导致脑血管疾病。中风倾向的自发性高血压大鼠 (SHRSP) 存在 BBB 缺陷，因此我们设计了本研究来检查这三种细胞类型在 SHRSP 中 BBB 功能障碍中的作用，以阐明这些细胞在BBB 更普遍。为此，我们采用了独特的 BBB 体外模型，其中可以测试细胞的各种组合。从 SHRSPs 和 Wistar Kyoto 大鼠 (WKYs) 中制备三种类型的细胞。然后将它们以各种组合共培养以构建体外 BBB 模型。通过测量跨内皮电阻和内皮单层对荧光素钠的渗透性来估计模型的屏障功能。体外模型显示 (1) SHRSPs 的 BECs 具有固有的较低屏障功能，(2) SHRSPs 的星形胶质细胞在 BECs 中诱导屏障功能的能力受损，尽管 (3) SHRSPs 和 WKYs 的周细胞和星形胶质细胞都可以增强BECs 在共培养条件下的屏障功能。此外，我们发现在使用 BEC 和/或 SHRSP 星形胶质细胞的模型中，claudin-5 的表达始终较低。这些结果表明，BBB 细胞（尤其是 BEC 和星形胶质细胞）之间的相互作用缺陷是 SHRSP 中 BBB 功能障碍的原因。