MMP-9 Upregulation is Attenuated by the Monoclonal TLR2 Antagonist T2.5 After Oxygen-Glucose Deprivation and Reoxygenation in Rat Brain Microvascular Endothelial Cells

Background: Blood-brain barrier (BBB) disruption plays a key role in the pathophysiology of acute ischemic stroke. Matrix metalloproteinases-2/9 (MMP-2/9) have been shown to participate in the disruption of the BBB and hemorrhagic transformation after cerebral ischemia. Toll-like receptor 2 (TLR2) may also be correlated with endothelial cell injury during ischemia-reperfusion events. However, the correlation between MMP-2/9 and TLR2 on endothelial cells after ischemia has not yet been evaluated. The aim of the study was to evaluate the impact of TLR2 and MMP-2/9 on tight junction proteins (TJs) after oxygen-glucose deprivation and reoxygenation (OGDR). Materials and methods: Rat primary brain microvascular endothelial cells (BMECs) were cultured. Quantitative real-time PCR and western blotting were used to measure the mRNA and proteins expression of TLR2 and MMP-2/-9. The protein expression of TJs was detected by western blotting and immunofluorescence. Results: MMP-9 significantly increased after OGDR. Protein and mRNA expression of TLR2 was also upregulated. However, claudin-5, occludin, collagen-IV, and ZO-1 were decreased after OGDR. When monoclonal anti-TLR2 antibody (T2.5) was added to BMECs after OGDR, MMP-9 was significantly downregulated, whereas occludin and collagen-IV had a tendency to increase. Conclusion: TLR2 antagonist T2.5 is able to downregulate the expression of MMP-9, and may constitute a therapeutic option for restoration of the BBB after OGDR.