Effect of hydrogen on activation of A1 astrocytes in hippocampus of mice with sepsis-associated encephalopathy / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of hydrogen on activation of A1 astrocytes in the hippocampus of mice with sepsis-associated encephalopathy (SAE).Methods:A total of 164 clean-grade healthy male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=41 each) using a random number table method: sham operation group (group Sham), sham operation plus hydrogen group (group Sham+ H 2), group SAE and SAE plus hydrogen group (group SAE+ H 2). The SAE model was established by cecal ligation and perforation.Group Sham+ H 2 and group SAE+ H 2 inhaled 2% hydrogen starting from 1 and 6 h after operation, respectively.Twenty mice in each group were selected to observe the 7-day survival rate after operation.The remaining mice were sacrificed at 12 h after operation, and brain tissues were removed for examination of the pathological changes in hippocampal CA1 region (with a light microscope) and for determination of the apoptosis in neurons (by TUNEL), co-expression of hippocampal glial fibrillary acidic protein (GFAP) and complement C3 (by immunofluorescence staining), expression of A1 astrocyte marker C3 (by Western blot), and contents of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-mobility group box 1 protein (HMGB1) (by enzyme-linked immunosorbent assay). The abnormal cell ratio and apoptosis rate were calculated.Six mice in each group were selected at 7 days after operation to perform Y-Maze paradigm. Results:Compared with group Sham, the 7-day survival rate after operation was significantly decreased, the abnormal cell ratio and apoptosis rate of hippocampal neurons were increased, the contents of TNF-α, IL-6 and HMGB1 were increased, the expression of C3 was up-regulated, the number of cells coexpressing GFAP and C3 was increased, the exploration time spent in the novel arm in Y-Maze paradigm was shortened, and the preference index was decreased in group SAE ( P<0.05). Compared with group SAE, the 7-day survival rate after operation was significantly increased, the abnormal cell ratio and apoptosis rate of hippocampal neurons were decreased, the contents of TNF-α, IL-6 and HMGB1 were decreased, the expression of C3 was down-regulated, the number of cells coexpressing GFAP and C3 was decreased, the exploration time spent in the novel arm in Y-Maze paradigm was prolonged, and the preference index was increased in group SAE+ H 2 ( P<0.05). There was no significant difference in each parameter mentioned above between Sham group and Sham+ H 2 group ( P>0.05). Conclusion:The mechanism by which hydrogen improves SAE may be related to inhibiting activation of A1 type astrocytes in mice.