Piperine Protects Against Cerebral Ischemic Injury by Regulating the Caspase-1-Mediated Pyroptosis Pathway

Jiayuan LuXinwen DaiSiyu XiBo WangPeng ZhangXueyan FuJuan LiuYiwei ZHang^*

• Ningxia Medical University, Yinchuan, China

Background: Ischemic stroke (IS) is a prevalent form of stroke and marked by high rates of morbidity, disability, and mortality. Piperine (Pip) is a bioactive dietary phytochemical known for its pharmacological properties, including anti-inflammatory effects. This study aims to investigate whether Pip attenuates cerebral ischemic injury by regulating the Caspase-1-mediated pyroptosis pathway. Methods: For the in vivo simulation of cerebral ischemia, the rat permanent middle cerebral artery occlusion (pMCAO) model was utilized. For the in vitro simulation, the BV-2 cells were subjected to oxygen-glucose deprivation (OGD). The recovery of neurological function in rats was assessed through multiple behavioral tests. Pathological changes in cerebral ischemic injury were observed using TTC staining, HE staining, and transmission electron microscopy. In in vivo and in vitro experiments, the potential protective mechanism of Pip in alleviating cerebral ischemic injury. Results: In the in vivo experiments, compared with the Sham group, the Model group exhibited significant neurological damage, increased infarct volume, brain tissue edema, and elevated protein and mRNA expression levels of pyroptosis-associated factors. By contrast, the Pip group demonstrated notable improvements in behavioral function, brain tissue morphology, and the expression levels of pyroptosis-related factors compared with the Model group. In the in vitro experiments, the protein and mRNA expression of pyroptosis-associated factors in the OGD group were significantly upregulated compared with that in the Con group. However, the expression of these factors in the OGD+Pip group was markedly reduced compared with that in the OGD group.Furthermore, when cells were treated with the Caspase-1 inhibitor Ac-YVAD-cmk, the results revealed a significant decrease in the protein expression of Caspase-1 and its downstream factors, GSDMD-N and IL-1β, compared with that in the OGD group.Notably, the protein expression of GSDMD-N and IL-1β in the Pip+Ac-YVAD-cmk group was significantly higher than in the Pip group, which suggests that the inhibition of Caspase-1 attenuated the suppressive effect of Pip on GSDMD-N and IL-1β expression. Conclusions: Pip exerts neuroprotective effects by modulating the Caspase-1-mediated pyroptosis pathway, which inhibits neuronal damage in the pMCAO model. These findings highlight the therapeutic potential of Pip in mitigating cerebral ischemic injury.