Benzydamine attenuates microglia-mediated neuroinflammation and ischemic brain injury by targeting cathepsin s.

Microglia, the primary immune cells of the central nervous system, play a crucial role in the neuroinflammatory processes following ischemic stroke. Targeting neuroinflammation is a promising strategy to enhance the outcomes of ischemic stroke. Benzydamine (BA), a well-known non-steroidal anti-inflammatory drug, has demonstrated potential in inhibiting pro-inflammatory cytokines across various disease models. However, the potential role of BA in microglial activation and post-stroke neuroinflammation remains unclear. Our study reveals that BA effectively suppresses the lipopolysaccharide (LPS)-stimulated pro-inflammatory responses of primary microglia, with high-dose BA (10 μM) suppressing LPS-induced inflammatory markers by up to 59.1 % in the mRNA levels of IL-1β. Furthermore, BA mitigated ischemic brain injury in experimental stroke mice. BA treatment also significantly attenuated neuroinflammatory responses and attenuates ischemic brain injury in experimental stroke mice. Further investigation revealed that BA reduces the release of the LPS-stimulated pro-inflammatory factors and activation of primary microglia by directly binding to and inhibiting the activity of cathepsin S (CTSS). In conclusion, our study identifies BA as a promising CTSS inhibitor with potential to suppress neuroinflammation following ischemic stroke. Our findings provide a theoretical basis for developing new neuroprotective strategies.