Molecular hydrogen (H) has been used in clinical cases. However, there are few studies of H therapy to treat sepsis, and anti-inflammatory mechanisms of H are mostly unknown. We aimed to confirm effects of H therapy on sepsis and reveal its therapeutic mechanism via RNA sequencing in multiple organs in septic mice.
Nine-week-old C57BL/6 male mice underwent cecal ligation and puncture (CLP) or sham procedure. Subsequently, the CLP model received immediate ± continuous inhalation of 7% H. Mice were observed for a week to assess survival rates. Serum inflammatory cytokines were evaluated at 24 h after CLP procedure. Liver, intestine, and lungs in CLP mice receiving 24-h ± H therapy were assessed by RNA sequencing. Data were analyzed with Ingenuity Pathways Analysis (QIAGEN Inc).
Seven-day survival rate in septic mice was significantly improved in the H inhalation group compared with that in the control group (75% versus 40%, P < 0.05). H treatment attenuated serum interleukin-6 and tumor necrosis factor-α levels at 24 h after CLP, and blood glucose levels were maintained in the H-treated group. In RNA sequencing, canonical pathway analysis revealed inactivity of various inflammatory signaling pathways, for example, acute phase response signaling and STAT3 pathways, in the liver and intestine in the CLP model after 24-h H inhalation. We detected significantly decreased expressions of upstream regulator genes such as the CD14 antigen gene in the liver and various cytokine receptor genes in the intestine and lungs in the H-treated group.
These findings may contribute to clarifying the mechanism of action of H therapy in sepsis.

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