Abstract: Objective To investigate the impact of midazolam on hypoxia-reoxygenation-induced neuronal injury based on mitogen-activated protein kinase (MAPK)/nuclear factor-κB (NF-κB) signaling pathway. Methods Mouse hippocampus neurons were cultured in vitro and the effects of 0, 5, 10, 40, 70 and 100 ng/mL midazolam on cell viability after hypoxia and reoxygenation were detected by MTT assay, and the best concentration was screened out. The cultured mouse hippocampus neurons were randomly separated into control group, model group (anoxic for 3 hours and reoxygenated for 12 hours), midazolam (70 ng/mL) group, C16-PAF (MAPK activator, 4 μmol/L) group, and midazolam (70 ng/mL) + C16-PAF group (4 μmol/L). The apoptosis of neurons was detected by Hoechst33258 staining and flow cytometry; the releases of lactate dehydrogenase (LDH), tumor necrosis factor-α(TNF-α), interleukin-18 (IL-18), and interleukin-17 (IL-17) and the levels of cellular superoxide dismutase (SOD) and catalase (CAT) were detected by ELISA; the expression of apoptosis proteins and MAPK/NF-κB pathway proteins were detected by western blotting. Results Compared with the control group, the neuron apoptosis rate, LDH, the TNF-α, IL-18, IL-17 releases, apoptosis protein caspase-9, Bax expression, and MAPK/NF-κB pathway p-p38 MAPK/p38 MAPK and p-NF-κB p65/NF-κB p65 levels were significantly increased in the model group (P＜0.05), the CAT and SOD levels in cells were significantly decreased (P＜0.05). Compared with the model group and midazolam+C16-PAF group, the neuron apoptosis rate, LDH, the TNF-α, IL-18, IL-17 releases, apoptosis protein caspase-9, Bax expression, and MAPK/NF-κB pathway p-p38 MAPK/p38 MAPK and p-NF-κB p65/NF-κB p65 levels were significantly decreased in the midazolam group (P＜0.05), the CAT and SOD activity in cells were significantly increased (P＜0.05); the neuron apoptosis rate, LDH, the TNF-α, IL-18, IL-17 releases, apoptosis protein caspase-9, Bax expression, and MAPK/NF-κB pathway p-p38 MAPK/p38 MAPK and p-NF-κB p65/NF-κB p65 levels were significantly increased in the C16-PAF group(P＜0.05), the CAT and SOD levels in cells were significantly decreased (P＜0.05). Conclusions Midazolam can reduce the expression of inflammatory cytokines by inhibiting the activation of MAPK/NF-κB signaling, thereby inhibiting the inflammatory and oxidative stress responses induced by hypoxia and reoxygenation, reducing neuronal cell damage and its apoptosis rate.

Key words: midazolam, mitogen-activated protein kinase/nuclear transcription factor-κB, hypoxia and reoxygenation, neuron, injury