Epigallocatechin gallate ameliorates brain injuries after intracerebral hemorrhage by inhibiting ferroptosis through upregulation of Nrf2-Keap1 pathway

Intracerebral hemorrhage (ICH) has high mortality and disability with limited efficient therapies. The inhibition of ferroptosis is implicated in the prognosis of ICH. Epigallocatechin gallate (EGCG) has iron chelating, anti-inflammatory and free radical scavenging properties, which connected with Nrf2-Keap1 pathway in previous researches. Our investigation aimed to identify the role of EGCG on ferroptosis in ICH rats and the underlying mechanisms through Nrf2-Keap1 pathway. In this study we observed that EGCG treatment effectively reduced hematoma volume, cellular destruction of brain tissue and ferroptosis in neuronal cells, and improved neurobehavioral outcomes in rat model of ICH. Our further studies showed that EGCG promoted the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), stimulated Nrf2-Keap1 complex releasing Nrf2 and promoted the translocation of Nrf2 from the cytoplasm to the nucleus, and regulated the downstream ferroptosis-regulated proteins to inhibit ferroptosis, while Nrf2 inhibitor reversed the anti-ferroptosis effect, suggesting that EGCG inhibit ferroptosis by upregulating Nrf2. Moreover, ultilizing the in vitro ICH model, we revealed that when Keap1 is silenced, the regulation of ferroptosis-related mRNA by EGCG through Nrf2 was enhanced, which is direct opposite of the Nrf2 silencing result, indicating that Nrf2-Keap1 pathway plays an important role in EGCG treatment after ICH. Our study confirmed for the first time that EGCG could reduce the iron deposition by regulating downstream ferroptosis-related proteins via Nrf2-Keap1 pathway and inhibit ferroptosis after ICH, indicating that EGCG could be a potential drug for the treatment of ICH.