Objective: To evaluate protective effects of inhaled hydrogen gas (H2) on cognitive function in a murine model of sepsis-associated encephalopathy (SAE).
Methods: A total of 84 male ICR mice, weighing 20-25 g, aged 6-8 weeks, were randomly divided into 4 groups of sham, sham+H2, sepsis and sepsis+H2. Sepsis was established by cecal ligation and puncture (CLP). Mice in sham+H2 and sepsis+H2 groups received 2% H2 inhalation for 1 h at 1 h and 6 h after sham operation or CLP operation respectively. The changes of neurological function and neuronal damage in hippocampal CA1 region were observed at 24 h post-operation. The activities of superoxide dismutase (SOD) and catalase (CAT) and the levels of malondialdehyde (MDA) and 8-iso-prostaglandin F2α (8-iso-PGF2α) in sera and hippocampus were detected at 24 h post-operation. The changes of cognitive function were observed by Y-maze test and fear conditional test at days 3 to 14 post-operation.
Results: Compared with sham group, the neurological function significantly declined and neurons in hippocampal CA1 region were significantly damaged; the activities of SOD and CAT markedly decreased while the levels of MDA and 8-iso-PGF2α markedly increased in sera and hippocampus; the time in new zone and the percentage of freezing time dramatically decreased at days 3 to 14 post-operation in sepsis group (P < 0.05) . Compared with sepsis group, neurological function significantly improved and damaged neurons in hippocampal CA1 region significantly reduced; the activities of SOD and CAT markedly increased and the levels of MDA and 8-iso-PGF2α markedly decreased in sera and hippocampus; the time in new zone and the percentage of freezing time dramatically increased at days 3 to 14 post-operations in sepsis+H2 group (P < 0.05).
Conclusion: H2 inhalation can significantly alleviate neuronal damage and improve cognitive dysfunction in CLP-induced SAE mice. And it is probably associated with the increased activities of antioxidant enzymes and the reduced levels of oxidative products.