Mechanism of Retigabine-mediated TLR4-TRIF Pathway on the Inflammatory Response in Rats with Ischemic Stroke - Mei Li; Jing Zhao; Aihong Li (Journal of Animal and Plant Sciences, 2026)
Ischemic stroke (IS) leads to cerebral tissue hypoxia and energy disruption due to the interruption of cerebral blood flow, which induces cellular damage and inflammation. This study was to investigate whether retigabine (RET) alleviates brain inflammation in IS rats by modulating the Toll-like receptor 4-TIR domain-containing adaptor inducing interferon (IFN)-beta (TLR4-TRIF) pathway and explores the underlying mechanisms. Rat hippocampal neurons (HT22) were divided into Group A (blank control), Group B (H2O2-induced hypoxia for 1 hour), and Group C (treatment with 5 µg/mL RET after H2O2 exposure). Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Additionally, cell apoptosis and reactive oxygen species (ROS) levels were assessed. Rats were further Assigned to sham surgery group, IS model group (middle cerebral artery occlusion via the filament method), and RET group (intraperitoneal injection of 5 mg/kg RET 1-hour post-surgery). Comparative endpoints included neurological function scores, infarct volume, brain inflammatory cytokines, and protein expression of the TLR4-TRIF pathway. Cell viability in Group B and Group C was dramatically reduced versus Group A (P≤0.05). However, versus Group B, Group C exhibited an increase in cell survival, with reduced apoptosis, ROS, tumor necrosis factor (TNF)-α), and interleukin (IL)-1β levels (P≤0.05). Additionally, both IS group and RET group had higher neurological function scores and infarct volumes versus sham group (P≤0.05). RET group showed a prominent reduction in these parameters versus model group. Moreover, TNF-α, C-reactive protein, IL-6, and expressions of TLR4, TRIF, TRIF-related adaptor molecules, IFN regulatory factor 3, and IFN-beta proteins were all markedly decreased in RET group (all P≤0.05). RET exerts neuroprotective effects by inhibiting TLR4-TRIF signaling, thereby alleviating brain inflammation induced by IS.
Keywords: journal article; Retigabine; TLR4-TRIF pathway; ischemic stroke; inflammatory response; mechanism