BCL2 and brain injury: In a neonatal rat hypoxic–ischemic brain injury (HIBI) model, hydrogen significantly reduced the Bax/Bcl-2 ratio by up-regulating the expression of the anti-apoptotic protein Bcl-2, while down-regulating the expression of the pro-apoptotic protein Bax and the apoptosis-executing enzyme caspase-3, leading to a reduction in apoptosis (Wang et al., 2020).