ObjectiveTo investigate the protective effect of resveratrol against blood-brain barrier damage in a rat model of cerebral ischemia-reperfusion and to determine whether this effect is mediated by the C-C motif chemokine ligand 3 (CCL3)/C-C chemokine receptor type 5 (CCR5) signaling pathway　Methods　A total of 100 specific pathogen-free (SPF) male Sprague-Dawley (SD) rats, aged 6-8 weeks, were randomly divided into five groups: sham-operated (Sham), model (MCAO), resveratrol-treated (Res), resveratrol+CCR5 agonist (Res+Agonist), and resveratrol+CCR5 antagonist (Res+Antagonist) groups. The MCAO, Res, Res+Agonist, and Res+Antagonist groups were subjected to middle cerebral artery occlusion (MCAO) for 45 min followed by reperfusion to establish the rat model of cerebral ischemia, while the Sham group underwent carotid artery exposure without ischemia. After reperfusion, resveratrol (60 mg/kg) was intraperitoneally injected in Res, Res+Agonist and Res+Antagonist groups, and an equal volume of normal saline was injected in Sham and MCAO groups. Thirty minutes later, CCR5 agonist (20 μg/kg) was injected via the tail vein in the Res+Agonist group, CCR5 inhibitor (1 mg/kg) was injected via the tail vein in the Res+Antagonist group, and the equal volume of normal saline was injected via the tail vein in the Res, Sham and MCAO groups. Thereafter, resveratrol, CCR5 agonist, CCR5 inhibitor, or saline were administered every 24 hours for 3 consecutive days. After modeling, cerebral infarct volume was evaluated by 2,3,5‑triphenyltetrazolium chloride (TTC) staining. Blood‑brain barrier (BBB) permeability was assessed by Evans blue extravasation. Serum levels of the pro‑inflammatory cytokines interleukin‑1β (IL‑1β), tumor necrosis factor‑α (TNF‑α), and CCL3 were measured by enzyme‑linked immunosorbent assay (ELISA). Histopathological changes in brain tissue were observed by hematoxylin and eosin (HE) staining and Nissl staining. Immunofluorescence staining was used to detect the fluorescence intensity of the microglial marker ionized calcium‑binding adapter molecule 1 (Iba‑1) and CCR5. Western blotting analysis was used to detect proteins associated with the CCL3/CCR5 signaling pathway (CCL3, CCR5) in brain tissue, serum pro-inflammatory cytokines [phosphorylated nuclear factor-kappa B (p-NF-κB)] and blood-brain barrier-related proteins [matrix metalloproteinase 9 (MMP9) and occludin]. ResultsCompared with the Sham group, the MCAO group exhibited significantly increased levels of all injury parameters, including cerebral infarct volume, Evans blue extravasation rate in brain tissue, serum levels of the pro‑inflammatory cytokines (IL-1β, TNF-α, and CCL3), the rate of Iba-1- and CCR5-positive immunofluorescence signals in brain tissue, and the protein expression levels of CCL3, CCR5, p-NF-κB, and MMP9 (all P<0.001), accompanied by markedly decreased expression of occludin (P<0.001). HE and Nissl staining revealed pronounced histopathological damage in the MCAO group.Compared with the MCAO group, the Res group showed significant reductions in all the aforementioned injury indicators and a significant increase in occludin expression (P<0.01), together with ameliorated histopathological changes. Compared with the Res group, the Res+Agonist group displayed significantly elevated injury indicators and decreased occludin expression (P<0.05), with aggravated brain tissue damage. In contrast, the Res+Antagonist group exhibited significant decreases in injury indicators and a significant increase in occludin expression (P<0.05), along with further alleviation of histopathological injury. ConclusionResveratrol attenuates peripheral inflammation in cerebral ischemia‑reperfusion injury by targeting the CCL3/CCR5 signaling pathway, thereby exerting a protective effect on the blood‑brain barrier.