Objective:To evaluate the effect of hydrogen on mitochondrial dynamics in hippocampus of mice with sepsis-associated encephalopathy (SAE).Methods:A total of 224 clean-grade healthy male C57 mice, weighing 20-25g, aged 6-8 weeks, were divided into 4 groups ( n=56 each) using a random number table method: sham operation group (group Sham), sham operation + hydrogen group (group Sham+ H 2), SAE group and SAE + hydrogen group (group SAE+ H 2). Sepsis was produced by cecum ligation and puncture (CLP). Sham+ H 2and SAE+ H 2 groups inhaled 2% hydrogen for 1 h starting from 1 and 6 h after CLP, respectively.The postoperative 7-day survival rate was recorded.Brain tissues were obtained at 24 h after operation for examination of the pathological changes in hippocampal CA1 region (with a light microscope) and for determination of mitochondrial membrane potential (MMP) (by fluorescence spectrophotometry) and ATP content (by a bioluminescence assay) in hippocampal tissues.At 6, 12 and 24 h after operation, hippocampal mitochondria were isolated for determination of the expression of dynamin-related protein 1 (Drp1) and the mitochondrial fusion proteins mitofusin 2 (Mfn2) (by Western blot). Results:Compared with group Sham, the postoperative 7-day survival rate was significantly decreased, the contents of MMP and ATP were decreased, the expression of Drp1 was up-regulated, and the expression of Mfn2 was down-regulated( P<0.05), the pathological changes were aggravated in hippocampal CA1 region in SAE and SAE+ H 2 groups, and no significant change was found in the parameters mentioned above in group Sham+ H 2 ( P>0.05). Compared with group SAE, the postoperative 7-day survival rate was significantly increased, the contents of MMP and ATP were increased, the expression of Drp1 was down-regulated, and the expression of Mfn2 was up-regulated( P<0.05), the pathological changes were attenuated in hippocampal CA1 region in group SAE+ H 2. Conclusion:The mechanism by which hydrogen improves mitochondrial function is probably associated with promoting mitochondrial fusion and inhibiting mitochondrial fission in hippocampus of mice with SAE.

Objective:To evaluate the effect of hydrogen on lipopolysaccharide (LPS)-caused inflammatory responses in BV-2 microglia and the role of autophagy.Methods:The BV-2 microglial cells cultured in vitro were seeded in 6- or 96-well plates and were divided into 4 groups ( n=24 each) using a random number table method: control group (group C), group LPS, hydrogen-rich medium group (group H) and autophagy inhibitor 3-methylpurine group (group 3-MA). In group C, cells were cultured in MEM culture medium supplemented with 15% fetal bovine serum for 24 h. In group LPS, LPS was added at a final concentration of 1 μg/ml, and cells were incubated for 24 h. In group H, LPS was added at a final concentration of 1 μg/ml, the culture medium was replaced with a hydrogen-rich medium at a final concentration of 0.6 mmol/L, and cells were incubated for 24 h. In group 3-MA, 3-methylpurine was added at a final concentration of 2 mmol/L, and the subsequent treatment was similar to those previously described in group H. The cell survival rate was detected by CCK-8 assay.The concentrations of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-10 and transforming growth factor-β (TGF-β) in supernatant were detected by enzyme-linked immunosorbent assay.The percentage of ionized calcium binding adaptor molecule-1 (Iba-1) +, Iba-1 + CD86 + and Iba-1 + CD206 + cells was detected by flow cytometry.The expression of microtubule-associated protein 1 light chain 3 Ⅰ (LC3 Ⅰ), LC3Ⅱ, Beclin-1 and p62 was detected by Western blot, and the ratio of LC3Ⅱ/LC3Ⅰ was calculated. Results:There was no significant difference in the cell survival rate among the four groups ( P>0.05). Compared with group C, the concentrations of TNF-α, IL-6, IL-10 and TGF-β and percentage of Iba-1 +, Iba-1 + CD86 + and Iba-1 + CD206 + cells were significantly increased in LPS, H and 3-MA groups, the LC3Ⅱ/LC3Ⅰ ratio and Beclin-1 expression was significantly down-regulated, and p62 expression was up-regulated in LPS and 3-MA groups, and the ratio of LC3LC3Ⅱ/LC3Ⅰ and Beclin-1 expression was significantly up-regulated, and p62 expression was down-regulated in group H ( P<0.05). Compared with group LPS, the concentrations of TNF-α and IL-6 were significantly decreased, the concentrations of IL-10 and TGF-β were increased, the percentage of Iba-1 + and Iba-1 + CD86 + cells were decreased, the percentage of Iba-1 + CD206 + cells was increased, the LC3Ⅱ/LC3Ⅰ ratio and Beclin-1 expression was up-regulated, and p62 expression was down-regulated in group H ( P<0.05), and no significant change was found in the above indexes in group 3-MA ( P>0.05). Compared with group H, the concentrations of TNF-α and IL-6 were significantly increased, the concentrations of IL-10 and TGF-β were decreased, the percentage of Iba-1 + and Iba-1 + CD86 + cells was increased, the percentage of Iba-1 + CD206 + cells was decreased, the LC3Ⅱ/LC3Ⅰ ratio and Beclin-1 expression was down-regulated, and p62 expression was up-regulated in group 3-MA ( P<0.05). Conclusion:The mechanism by which hydrogen reduces LPS-caused inflammatory responses in BV-2 microglia is related to enhancing autophagy and inhibiting microglial activation.

Objective: To evaluate the effect of hydrogen on mitochondrial biosynthesis in the hippocampus of mice with sepsis-associated encephalopathy (SAE). Method: Two hundred and twenty-four healthy clean-grade male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups (n=56 each) using a random number table method: sham operation group (group SH), sham operation plus hydrogen group (group SH+ H₂), group SAE, and SAE plus hydrogen group (group SAE+ H₂). The model of SAE was established by cecal ligation and puncture in anesthetized mice.Group SH+ H₂ and group SAE+ H₂ inhaled 2% hydrogen for 1 h starting from 1 and 6 h after operation, respectively.Twenty mice were selectde to record the postoperative 7-day survival rate.The remaining animals were sacrificed at 24 h after operation, and brain tissues were taken for examination of the pathological changes in hippocampal CA1 region (with a light microscope) and for determination of neuronal apoptosis (by TUNEL), mitochondrial membrane potential (MMP) (by fluorescence spectrophotometry) and ATP content (by a bioluminescence assay). The apoptosis rate was calculated.The expression of peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) in hippocampus was determined by Western blot at 6, 12 and 24 h after operation. Results: Compared with group SH, the postoperative 7-day survival rate was significantly decreased, the apoptosis rate of hippocampal neurons was increased, the contents of MMP and ATP were decreased, and the expression of PGC-1α was up-regulated in SAE and SAE+ H₂groups (P<0.05), and no significant change was found in the parameters mentioned above in group SH+ H₂(P>0.05). Compared with group SAE, the postoperative 7-day survival rate was significantly increased, and the apoptosis rate of hippocampal neurons was decreased, the contents of MMP and ATP were increased, and the expression of PGC-1α was up-regulated (P<0.05), and the pathological changes of hippocampal tissues were significantly attenuated in group SAE+ H₂. Conclusion The mechanism by which hydrogen mitigates SAE may be related to promoting mitochondrial biosynthesis in mice.