Benzbromarone Attenuates Collagen-evoked Platelet Activation and Cerebral Ischemia-reperfusion Injury in a Rat Model

BACKGROUND: Benzbromarone (BBR), a clinical drug for gout, has recently been identified as an inhibitor of Heat Shock Protein 47 (HSP47). HSP47 is known to participate in platelet- collagen interactions and thrombus formation. However, whether BBR exerts antiplatelet and neuroprotective effects in ischemic stroke remains unclear. METHODS: Bleeding risk and cytotoxicity of BBR were assessed using tail bleeding time, coagulation parameters, LDH and CCK-8 assays, with aspirin and clopidogrel as comparators. The effects of BBR (1, 5, 10 μM) on collagen-induced platelet aggregation, adhesion, calcium mobilization and clot retraction were examined. The antithrombotic potential of BBR was evaluated in a FeCl3-induced carotid artery thrombosis model, and its neuroprotective potential in a Middle Cerebral Artery Occlusion (MCAO) model in rats. Phosphorylation levels of the Syk-PLCγ2-PKC and PI3K-Akt-GSK3β pathways were detected by western blotting. RESULTS: In this study, BBR exhibited low bleeding risk and low cytotoxicity, similar to aspirin and clopidogrel. BBR dose-dependently reduced collagen-induced platelet aggregation, adhesion, [Ca2+] mobilization, and clot retraction. BBR delayed the Time to Occlusion (TTO) and inhibited arterial thrombosis. In MCAO rats, BBR also reduced infarct volume and ameliorated neurological deficits. Western blotting revealed that BBR decreased the phosphorylation levels of proteins in the Syk-PLCγ2-PKC and PI3K-Akt-GSK3β pathways. DISCUSSION: As a known inhibitor of HSP47, BBR may suppress collagen-induced platelet activation and arterial thrombosis, possibly through modulating downstream signaling pathways of GPVI. Compared with conventional antiplatelet agents, BBR showed a favorable safety profile in rats, without significantly prolonging bleeding time or affecting liver and kidney function. These findings suggest that BBR represents a promising antiplatelet candidate with both efficacy and safety for ischemic stroke management. CONCLUSION: The present study demonstrates that BBR inhibits platelet activation and thrombosis, and attenuates cerebral ischemia-reperfusion injury in rats. Its protective effect may be associated with suppression of GPVI-related signaling pathways. BBR thus warrants further investigation as a potential candidate for acute-stage treatment of ischemic stroke.