TLR4 and brain infarction: The TLR4 is a specific receptor for LPS and plays a crucial role in inflammation mediated by the microbiota-gut-brain axis mechanisms.77 A major producer of LPS in the gut microbiota is Gram-negative bacteria, with f_Enterobacteriaceae being a key example.78 A recent study suggested the excessive proliferation of f_Enterobacteriaceae exacerbates systemic inflammation and worsens cerebral infarction via the LPS/TLR4 pathway.79 In our study, we found a significant increase in the abundance of f_Enterobacteriaceae and the levels of LPS in the feces of neonatal rats after HI insult.