Neuroprotective role of Nrf2 on hypoxic-ischemic brain injury in neonatal mice

Inflammation and oxidative stress play a key role in mediating the pathophysiology of hypoxic-ischemic (HI) brain injury. Nrf2 is a transcriptional factor that contributes to the innate defense of the body against oxidative stress and inflammation. The current study investigated the effect of Nrf2 in neonatal HI brain injury using Nrf2^-/- mice. Nrf2^-/- and wild-type Nrf2^+/+ mice on a C57BL/6J background at postnatal day 9 underwent unilateral common carotid artery ligation, followed by hypoxia. Brain damage was determined by infarct size measurement. Apoptosis was evaluated by measuring the expression of Bax and Bcl-2. The levels of inflammatory cytokines and mediators involved in oxidative stress were measured. Nrf2 knockout exacerbated HI injury-induced brain infarct and cell apoptosis in the brain. Nrf2^-/- mice showed increased inflammatory cytokines and MDA, and reduced activities of antioxidant enzymes including CAT, GSH-Px, and SOD. Nrf2^-/- mice showed reduced HO-1 expression after HI injury compared with wild-type mice. This study supported a protective effect of Nrf2 in neonatal HI brain injury.