Silymarin prevents NLRP3 inflammasome activation and protects against intracerebral hemorrhage

Inflammatory response mediates secondary injury during intracerebral hemorrhage (ICH). In the present study, we determined oxidative stress and involvement of NLRP3 in ICH injury and analyzed whether silymarin might offer protective effect against ICH injury. Post 24h after ICH injury there was increased oxidative stress markers (reactive oxygen species (ROS) and lipid peroxides) compared to sham group. Silymarin (200mg/kg) treatment 30 mins post ICH injury prevented increase in oxidative stress markers and up-regulated antioxidant status. Further, there was significant increase in nuclear levels of NF-κB-p65 and pro-inflammatory cytokine expressions post ICH injury. NLRP3 inflammasome activation and downstream targets such as caspase-1 and IL-1β expressions were significantly up regulated in ICH injury. Silymarin treatment significantly down regulated the inflammatory responses by suppressing NF-κB-p65 levels and inflammasome-mediated caspase-1/IL-1β expressions. Further, treatment with silymarin post ICH injury increased Nrf-2/HO-1 and thereby improved overall cytoprotection. These findings together show that silymarin acts as neuroprotective compound by preventing inflammatory activation and up regulating Nrf-2/HO-1 signaling post ICH injury.