Sevoflurane post-conditioning increases nuclear factor erythroid 2-related factor and hemoxygenase-1 expression via protein kinase C pathway in a rat model of transient global cerebral ischemia

Abstract

Introduction: The antioxidant mechanism of sevoflurane postconditioning-induced neuroprotection remains unclear. We determined whether sevoflurane postconditioning induces nuclear factor erythroid 2-related factor (Nrf2, a master transcription factor regulating antioxidant defense genes) and heme oxygenase-1 (HO-1, an antioxidant enzyme) expression, and whether protein kinase C (PKC) is involved in Nrf2 activation in a rat model of transient global cerebral ischemia/reperfusion (IR) injury.

Methods: 86 rats were assigned to five groups: sham (n=6), control (n=20), sevoflurane postconditioning (two cycles with 2 vol% sevoflurane inhalation for 10 min, n=20), chelerythrine (a PKC inhibitor

5 mg kg-1 intravenous administration, n=20), and sevoflurane postconditioning plus chelerythrine (n=20). Each group was further divided into two subgroups, based on the day of sacrifice (1 or 7 days after ischemia), of 10 rats each, except sham group (n=3). The levels of nuclear Nrf2 and cytoplasmic HO-1 were assessed.

Results: On day 1 post-ischemia, but not day 7, Nrf2 and HO-1 expression was significantly higher in the sevoflurane postconditioning group than in the control group. Chelerythrine administration reduced Nrf2 and HO-1 expression induced by sevoflurane postconditioning.

Conclusions: Sevoflurane postconditioning increased Nrf2/HO-1 expression via PKC signaling in the early phase after transient global cerebral IR injury, suggesting that activation of antioxidant enzymes may be responsible for sevoflurane postconditioning-induced neuroprotection in the early phase after cerebral IR injury.