Limb Ischemic Perconditioning Attenuates Blood-Brain Barrier Disruption by Inhibiting Activity of MMP-9 and Occludin Degradation after Focal Cerebral Ischemia

Abstract

Remote ischemic perconditioning (PerC) has been proved to have neuroprotective effects on cerebral ischemia, however, the effect of PerC on the BBB disruption and underlying mechanisms remains largely unknown. To address these issues, total 90 adult male Sprague Dawley (SD) rats were used. The rats underwent 90-min middle cerebral artery occlusion (MCAO), and the limb remote ischemic PerC was immediately applied after the onset of MCAO. We found that limb remote PerC protected BBB breakdown and brain edema, in parallel with reduced infarct volume and improved neurological deficits, after MCAO. Immunofluorescence studies revealed that MCAO resulted in disrupted continuity of claudin-5 staining in the cerebral endothelial cells with significant gap formation, which was significantly improved after PerC. Western blot analysis demonstrated that expression of tight junction (TJ) protein occludin was significantly increased, but other elements of TJ proteins, claudin-5 and ZO-1, in the BBB endothelial cells were not altered at 48 h after PerC, compared to MCAO group. The expression of matrix metalloproteinase (MMP-9), which was involved in TJ protein degradation, was decreased after PerC. Interestingly, phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2), an upstream of MMP-9 signaling, was significantly reduced in the PerC group. Our data suggest that PerC inhibits MMP-9-mediated occludin degradation, which could lead to decreased BBB disruption and brain edema after ischemic stroke.Key words: ischemic stroke, remote ischemic perconditioning, blood-brain barrier, tight junction, matrix metalloproteinasesThe blood-brain barrier (BBB) is a physical and metabolic interface that segregates the central nervous system (CNS) from the peripheral circulation in addition to regulating the CNS microenvironment [1]. Under physiological conditions, BBB integrity is maintained by endothelial cell through tight junctions (TJs) and the basal lamina, limiting paracellular movement of ions, solutes, and water [2]. Yet, TJs are key components of the BBB structure that seal the gaps between adjacent endothelial cells and restrict paracellular permeability [3]. The TJ proteins, occludin and claudins, are important molecules in forming this seal [4]. In vivo, cerebral ischemia induces claudin-5

Antiretroviral Treatment with Efavirenz Disrupts the Blood-Brain Barrier Integrity and Increases Stroke Severity

“…Claudin-5 was demonstrated to be an important contributor to BBB integrity61 and its upregulation correlates with a protective effect against CNS tissue injury62. Similar observations have been made for ZO-1 and occludin both in vitro and in vivo 62636465. In our model system, exposure to Efavirenz selectively decreased the levels of claudin-5.…”

Regulation of Caveolin-1 Expression Determines Early Brain Edema After Experimental Focal Cerebral Ischemia

“…[25][26][27] We proceeded to evaluate whether Cav-1 regulation could induce alterations in tight junction (TJ) protein expression and MMP activity. Figure 5 indicates that transplantation of transfected ECs expressing Cav-1 to Cav-1 −/− mice trends in the direction of reversing the Cav-1 deficiency-induced loss in TJ proteins, including claudin-5, occludin, zona occludens-1, and JAM-A.…”

Limb remote ischaemic postconditioning‐induced elevation of fibulin‐5 confers neuroprotection to rats with cerebral ischaemia/reperfusion injury: Activation of the AKT pathway

“…The immunofluorescence staining for claudin-5 and occludin was performed as described previously. 31 Briefly, the brain tissues were embedded in paraffin and sectioned. Then the sections were deparaffinized, incubated in microwave heat-induced epitope retrieval.…”