Kelch-like ECH-associated Protein 1-dependent Nuclear Factor-E2–related Factor 2 Activation in Relation to Antioxidation Induced by Sevoflurane Preconditioning

Authors: Min Cai, M.D., Ph.D. et al     

Anesthesiology published on January 5, 2017

Background: The authors have reported that antioxidative effects play a crucial role in the volatile anesthetic-induced neuroprotection. Accumulated evidence shows that endogenous antioxidation could be up-regulated by nuclear factor-E2–related factor 2 through multiple pathways. However, whether nuclear factor-E2–related factor 2 activation is modulated by sevoflurane preconditioning and, if so, what is the signaling cascade underlying upstream of this activation are still unknown.

Methods: Sevoflurane preconditioning in mice was performed with sevoflurane (2.5%) 1 h per day for five consecutive days. Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion. Expression of nuclear factor-E2–related factor 2, kelch-like ECH-associated protein 1, manganese superoxide dismutase, thioredoxin-1, and nicotinamide adenine dinucleotide phosphate quinolone oxidoreductase-1 was detected (n = 6). The antioxidant activities and oxidative product expression were also examined. To determine the role of kelch-like ECH-associated protein 1 inhibition-dependent nuclear factor-E2–related factor 2 activation in sevoflurane preconditioning-induced neuroprotection, the kelch-like ECH–associated protein 1-nuclear factor-E2–related factor 2 signal was modulated by nuclear factor-E2–related factor 2 knockout, kelch-like ECH-associated protein 1 overexpression lentivirus, and kelch-like ECH-associated protein 1 deficiency small interfering RNA (n = 8). The infarct volume, neurologic scores, and cellular apoptosis were assessed.

Results: Sevoflurane preconditioning elicited neuroprotection and increased nuclear factor-E2–related factor 2 nuclear translocation, which in turn up-regulated endogenous antioxidation and reduced oxidative injury. Sevoflurane preconditioning reduced kelch-like ECH-associated protein 1 expression. Nuclear factor-E2–related factor 2 ablation abolished neuroprotection and reversed sevoflurane preconditioning by mediating the up-regulation of antioxidants. Kelch-like ECH-associated protein 1 overexpression reversed nuclear factor-E2–related factor 2 up-regulation and abolished the neuroprotection induced by sevoflurane preconditioning. Kelch-like ECH-associated protein 1 small interfering RNA administration improved nuclear factor-E2–related factor 2 expression and the outcome of mice subjected to ischemia/reperfusion injury.

Conclusions: Kelch-like ECH-associated protein 1 down-regulation–dependent nuclear factor-E2–related factor 2 activation underlies the ability of sevoflurane preconditioning to activate the endogenous antioxidant response, which elicits its neuroprotection.