MPO and injury: Hydrogen peroxide (H2O2) and chloride ion react to generate endogenous HOCl under the catalysis of myeloperoxidase (MPO) (Winterbourn and Kettle, 2000; Ulfig and Leichert, 2021), and the change of HOCl level is closely associated with the occurrence and development of numerous diseases, such as arthritis (Stamp et al., 2012), liver cirrhosis (Whiteman et al., 2005; Jaeschke and Hasegawa, 2006), kidney injury (Malle et al., 2003), and neuronal degeneration (Yap et al., 2006; Ray and Katyal, 2016).