Sleep loss in the rat increases blood-brain barrier permeability to circulating molecules by disrupting interendothelial tight junctions. Despite the description of the ultrastructure of cerebral microvessels and the evidence of an apparent pericyte detachment from capillary wall in sleep restricted rats the effect of sleep loss on pericytes is unknown. Here we characterized the interactions between pericytes and brain endothelial cells after sleep loss using male Wistar rats. Animals were sleep-restricted 20 h daily with 4 h sleep recovery for 10 days. At the end of the sleep restriction, brain microvessels (MVs) were isolated from cerebral cortex and hippocampus and processed for Western blot and immunocytochemistry to evaluate markers of pericyte-endothelial cell interaction (connexin 43, PDGFR-β), tight junction proteins, and proinflammatory mediator proteins (MMP9, A2A adenosine receptor, CD73, NFκB). Sleep restriction reduced PDGFR-β and connexin 43 expression in MVs; in addition, scanning electron microscopy micrographs showed that pericytes were detached from capillary walls, but did not undergo apoptosis (as depicted by a reduced active caspase-3 expression). Sleep restriction also decreased tight junction protein expression in MVs and increased BBB permeability to low- and high-molecular weight tracers in in vivo permeability assays. Those alterations seemed to depend on a low-grade inflammatory status as reflected by the increased expression of phosphorylated NFκB and A2A adenosine receptor in brain endothelial cells from the sleep-restricted rats. Our data show that pericyte-brain endothelial cell interaction is altered by sleep restriction; this evidence is essential to understand the role of sleep in regulating blood-brain barrier function.

中文翻译：

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睡眠不足会破坏周细胞-脑内皮细胞的相互作用，从而损害血脑屏障功能

大鼠的睡眠不足通过破坏内皮间紧密连接增加了循环分子的血脑屏障通透性。尽管对大脑微血管超微结构的描述和睡眠受限大鼠毛细血管壁明显的周细胞脱离的证据，但睡眠不足对周细胞的影响尚不清楚。在这里，我们使用雄性 Wistar 大鼠表征了睡眠不足后周细胞和脑内皮细胞之间的相互作用。动物每天限制睡眠 20 小时，睡眠恢复 4 小时，持续 10 天。在睡眠限制结束时，从大脑皮层和海马体中分离出脑微血管 (MV) 并进行蛋白质印迹和免疫细胞化学处理，以评估周细胞 - 内皮细胞相互作用的标志物（连接蛋白 43，PDGFR-β）、紧密连接蛋白、和促炎介质蛋白（MMP9、A2A 腺苷受体、CD73、NFκB）。睡眠限制降低了 MV 中 PDGFR-β 和连接蛋白 43 的表达；此外，扫描电子显微镜显微照片显示，周细胞与毛细血管壁分离，但未发生细胞凋亡（如活性 caspase-3 表达降低所示）。在体内渗透性测定中，睡眠限制还降低了 MV 中紧密连接蛋白的表达，并增加了 BBB 对低分子量和高分子量示踪剂的渗透性。这些改变似乎取决于低度炎症状态，这反映在睡眠受限大鼠脑内皮细胞中磷酸化 NFκB 和 A2A 腺苷受体的表达增加。我们的数据显示周细胞-脑内皮细胞的相互作用会因睡眠限制而改变；