RESUMO
Objective:To evaluate the effect of high-concentration hydrogen inhalation on sepsis-associated encephalopathy (SAE) in mice.Methods:Healthy male ICR mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=50 each) using the random number table method: sham operation group (Sham group), SAE group, sham operation plus high-concentration hydrogen group (Sham+ H 2 group), and SAE plus high-concentration hydrogen group (SAE+ H 2 group). SAE model was prepared by cecal ligation and puncture (CLP) in anesthetized animals.At 1 and 6 h after operation, Sham+ H 2 and SAE+ H 2 groups inhaled the mixture of hydrogen and oxygen (67% hydrogen-33% oxygen) for 1 h, and Sham and SAE groups inhaled the mixture of nitrogen and oxygen (67% nitrogen-33% oxygen) for 1 h. The postoperative 7-day survival rate was recorded.Cognitive function was assessed by Y maze test at days 3, 5 and 7 after operation.The mice were sacrificed at 24 h after operation, and hippocampal tissues were obtained for microscopic examination of the pathological changes of neurons in hippocampal CA1 region (with a light microscope) and for determination of normal neuron count, contents of tumor necrosis factor-ɑ (TNF-α) and high mobility group box-1 (HMGB1) (by enzyme-linked immunosorbent assay), mitochondrial membrane potential (MMP) (by fluorescence spectrophotometry) and content of mitochondrial ATP (by fluorescein-fluorescent enzyme luminescence method). Results:Compared with Sham group, the 7-day survival rate after operation, percentage of spontaneous alternation at each time point after operation, and the number of normal neurons were significantly decreased, the contents of TNF-ɑ and HMGB1 were increased, and the contents of ATP and MMP were decreased in SAE and SAE+ H 2 groups ( P<0.05), and no significant change was found in Sham+ H 2 group ( P>0.05). Compared with SAE group, the 7-day survival rate after operation, percentage of spontaneous alternation at each time point after operation, and the number of normal neurons were significantly increased, the contents of TNF-ɑ and HMGB1 were decreased, and the contents of ATP and MMP were increased in SAE+ H 2 group ( P<0.05). Conclusions:High-concentration hydrogen inhalation can reduce SAE, and the mechanism may be related to reduction of hippocampal inflammatory responses and improvement in mitochondrial function in mice.