Caveolin-1-Mediated Blood-Brain Barrier Disruption via MMP2/9 Contributes to Postoperative Cognitive Dysfunction.

Postoperative cognitive dysfunction (POCD) is a prevalent complication following major surgery, particularly in older adults, and is associated with increased morbidity, prolonged hospitalization, and reduced quality of life. Although blood-brain barrier (BBB) disruption has been implicated in POCD pathogenesis, the molecular mechanisms remain poorly defined. In this study, we identify Caveolin-1 (Cav-1), a membrane scaffolding protein highly expressed in endothelial cells (ECs), as a key regulator of BBB integrity and cognitive function following surgical trauma. Using a tibial fracture internal fixation model in mice, we observed a significant upregulation of Cav-1 in the hippocampus, accompanied by reduced expression of tight junctions (TJs) proteins (Claudin-5 and ZO-1), increased BBB permeability, and impaired performance in behavioral assays indicative of cognitive decline. Pharmacological inhibition of Cav-1 via methyl-β-cyclodextrin (MβCD) attenuated these effects, restoring TJs expression, reducing BBB leakage, and improving cognitive outcomes. To elucidate the underlying mechanism, we employed an in vitro inflammation model using LPS-stimulated brain microvascular ECs. Cav-1 upregulation was found to increase the expression of matrix metalloproteinases MMP2 and MMP9, which in turn degraded TJs. Inhibition of Cav-1 suppressed MMP2/9 expression and preserved barrier integrity, confirming a Cav-1/MMP2/9 signaling axis. These findings demonstrate that Cav-1 plays a central role in mediating BBB breakdown and postoperative cognitive impairment via MMP-dependent degradation of TJs. Targeting Cav-1 may offer a novel therapeutic strategy to preserve BBB function and reduce the incidence of POCD in surgical patients.