Perioperative orexin-A protects brain microvascular endothelial integrity in experimental sepsis-associated encephalopathy.

BACKGROUND: Sepsis-associated encephalopathy (SAE) represents a prevalent central nervous system complication in patients with blood-brain barrier (BBB) dysfunction as core pathogenic mechanism. Orexin-A (OXA) modulates inflammatory and oxidative responses, but its direct protective effect on brain microvascular endothelial cells (BMVECs) remains unreported. METHODS: In vivo, SAE was induced in mice by the cecal ligation and puncture (CLP), lateral ventricular administration of OXA is performed during the perioperative period. Survival, Y-maze, and open-field tests assessed cognition. BBB permeability was evaluated by cerebral water content and extravasation of Evans blue dye. Endothelial junctions, inflammation and neuronal damage were examined via VE-cadherin, ICAM-1/VCAM-1/IL-6, hematoxylin-eosin (HE) and Nissl staining. In vitro, LPS-stimulated bEnd.3 cells were treated with OXA or N-acetylcysteine (NAC). Oxidative stress (ROS, SOD, MDA/GSH), VE-cadherin, Occluding, ZO-1, γH2AX, and NF-κB activation were measured. RESULTS: OXA improved survival and cognitive performance, reduced BBB permeability, upregulated VE-cadherin expression, suppressed inflammatory responses, and alleviated neuronal damage. In LPS stimulation bEnd.3 cells, OXA and NAC similarly reduced ROS accumulation, restored VE-cadherin. OXA decreased γH2AX, and inhibited NF-κB activation as well as ICAM-1/VCAM-1 expression. CONCLUSION: OXA pretreatment protects against SAE by attenuating oxidative stress, suppressing NF-κB signaling activation, reducing inflammatory responses, and preserving endothelial junction integrity, including VE-cadherin-mediated adherens junctions, thereby mitigating blood-brain barrier disruption and improving behavioral performance in the CLP-induced SAE model.