Ac2-26 TFA is the active N-terminal peptide of Annexin A1 (AnxA1). The sequence contains 25 amino acids and the N-terminal is blocked by an acetyl group. In vivo, it can reduce acute lung injury induced by ischemia-reperfusion, while also reducing the expression of AnxA1 protein, and inhibiting the activation of NF-κB and MAPK pathways in damaged lung tissue.