Pomelo Peel Volatile Oil Alleviates Neuroinflammation On Focal Cerebral Ischemia Reperfusion Injury Rats Via Inhibiting Tlr4/Nf-Kappa B Signaling Pathway

Background: Restoration of blood flow during ischemic stroke leads to Cerebral Ischemia-Reperfusion Injury (CIRI) by activating neuroinflammatory cascades. Pomelo Peel Volatile Oil (PPVO) extracted from Citrus maxima (Burm.) from the genus Rutaceae, comprises some anti-inflammatory ingredients, such as limonene and beta-myrcene.Objective: The present study aimed to investigate the potential effect of PPVO on alleviating CIRI related to the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-Kappa B) pathway.Methods: Transient middle cerebral artery occlusion/reperfusion (tMCAO/R) was performed on 65 rats, which were then distributed into five groups (n = 13/group) depending on the intervention they received: Normal Saline (NS) group, normal Glycerin (GL) group, low-dose PPVO (LP, 10mg/kg) group, high-dose PPVO (HP, 30 mg/kg) group, and Sham-operated (SH) group. Neurological Deficit Scores (NDSs) and histological changes were evaluated. Infarct volumes were measured by 2,3,5-Triphenyltetrazolium Chloride (TTC) staining. The expression of TLR4 and neutrophil infiltration were detected by Immunofluorescence (IF) staining. Moreover, the downstream molecules of the TLR4/NF-Kappa B signaling pathway, such as IL-6, IL-1 beta, TNF-alpha, p-I Kappa B/I Kappa B, and p-NF-Kappa B p65/NF-Kappa B p65 were analyzed by Western Blot (WB).Results and Discussion: The results showed that PPVO (30 mg/kg) significantly decreased infarct volumes, improved neurological deficits and pathologic changes, inhibited TLR4/NF-Kappa B signaling pathway suppressed neutrophil infiltration, and suppressed pro-inflammatory cytokine release.Conclusion: It can be concluded that PPVO may alleviate neuroinflammation and protect against CIRI via inhibiting the TLR4/NF-Kappa B signaling pathway.