IntroductionIschemic stroke (IS) is one of the three main fatal disorders and is a major health challenge. 4-methylumbelliferone (4-MU) is one of the coumarin derivatives (7-hydroxy-4-methylcoumarin) with antioxidant and anti-inflammatory impact. This study was conducted to elucidate the neuroprotective effects and anti-inflammatory impact of 4-MU in a rodent model of IS.MethodsThe IS model was induced by middle cerebral artery occlusion (MCAO) for 1 hour and reperfusion was established for 24 hours. 44 Male Wistar rats were divided into four groups: 1) Sham, 2) MCAO, 3) MCAO + Vehicle, and 4) MCAO + 4-MU (25 mg/kg). Evaluation of neurological deficit was performed using Garcia's score. 2,3,5-triphenoyl-2H-tetrazolium chloride (TTC) staining was employed to measure infarct size. Nissl staining was applied to determine neuronal loss. Moreover, western blotting was utilized to detect the expression of the proteins relevant to the TLR4/NF-κB/NLRP3 axis (p-NF-κB p65, TLR4, NLRP3, IL-1β, IL-10, IL-18, ASC, and Caspase-1).ResultsIt was observed that MCAO caused neurological deficit (P<0.0001), infarct (P<0.0001), and neuronal loss (P<0.002); up-regulated NLRP3 (P<0.0001), TLR4 (P<0.0001), p-NF-κB p65 (P<0.0005), IL-1β (P<0.0014), IL-18 (P<0.0001), ASC (P<0.0027), and Caspase-1 (P<0.0052); and reduced IL-10 concentrations (P<0.0024). Administration of 4-MU (25 mg/kg) quickly after reperfusion reduced neurological deficit (P<0.0001), infarct size (P<0.0001), neuronal loss (P<0.0058), and down-regulated NLRP3 (P<0.0257), TLR4 (P<0.0001), p-NF-κB p65 (P<0.0075), IL-1β (P<0.0106), IL-18 (P<0.0005), ASC (P<0.0072), and Caspase-1 (P<0.0315), and increased IL-10 concentrations (P<0.0215).ConclusionThese results indicate that 4-MU can attenuate injury after MCAO by suppressing the TLR4/NF-κB/NLRP3 axis. Our findings show that 4-MU can be considered a novel therapeutic compound to cure IS.
