Emodin influence pyroptosis-related Caspase 1-GSDMD axis alleviated cerebral ischemia-reperfusion injury in rats

Background Cerebrovascular disease encompasses a wide range of conditions characterized by cerebrovascular lesions or disruptions in blood flow. Ischemic stroke, among these conditions, is the most prevalent and is known for its substantial morbidity, disability, and mortality rates, making it a leading cause of global disability. Effective management of ischemia-reperfusion injury holds paramount importance in stroke treatment, regardless of whether thrombolytic therapy is administered. Previous studies have shown that Emodin exhibits anti-inflammatory and neuroprotective properties, providing protection against ischemia-reperfusion injury in various organs by modulating pyroptosis. However, the precise molecular mechanisms underlying the effects of Emodin in cerebral ischemia-reperfusion injury remain poorly understood. Therefore, the objective of this study was to elucidate the neuroprotective mechanisms of Emodin in the context of ischemic stroke. Methods SD rats were randomly assigned to different groups, including control group, sham operation group, model group, and Emodin intervention group with varying dosages. Cerebral ischemia-reperfusion injury was induced using the middle cerebral artery occlusion (MCAO) method. Intraperitoneal injections of 10mg/kg, 20mg/kg and 40 mg/kg Emodin were administered to assess neurological changes in the rats. The modified Neurological Severity Score (mNSS) was used to evaluate neurological deficits. The infarct volume ratio was determined through TTC staining, while HE staining was employed to observe pathomorphological changes. Using Western blotting (WB) technique and immunofluorescence, we investigated the expression levels and cellular localization of proteins associated with cell pyroptosis, including NLRP3, Caspase 1 and GSDMD. Additionally, enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of IL-1β and IL-18. The whole animal study was approved by the Affiliated Hospital of Zunyi Medical University (approval number KLLY(A)-2021-083) and all methods are reported in accordance with ARRIVE guidelines. Results Emodin exhibits significant beneficial effects in improving neurological deficits caused by cerebral ischemia-reperfusion injury. It effectively reduces the ratio of infarct volume, alleviates cytopathic damage and suppresses the expression of pyroptosis-related proteins, including NLRP3, Caspase 1 and GSDMD. Furthermore, Emodin decreases the levels of pro-inflammatory cytokines IL-1β and IL-18, thus attenuating the inflammatory response. Conclusions The expression of pyroptosis-related proteins is upregulated in rats after cerebral ischemia-reperfusion injury. Emodin demonstrates neuroprotective effects against cerebral ischemia-reperfusion injury in rats, potentially by modulating the expression of pyroptosis-related proteins mediated through the Caspase 1-GSDMD axis.