Influences of hydrogen-rich saline on acute kidney injury in severely burned rats and mechanism

Results: (1) The renal tubular structure of rats in sham injury group at PIH 72 was complete with no inflammatory cell infiltration and no cellular degeneration or necrosis. Since PIH 6, the changes such as vacuolation and shape change of cells and aggregation of broken protein in renal tubules were observed in rats of burn group, and all these changes deteriorated with time. The renal injury of rats in hydrogen-rich saline group at different post injury time points were relieved compared with those of rats in burn group at the corresponding time points. The renal tubular injury scores of rats in burn group and hydrogen-rich saline group at PIH 6, 24, and 72 were significantly higher than the score in sham injury group at PIH 72 (P<0.05). The renal tubular injury scores of rats in hydrogen-rich saline group were significantly lower than those in burn group at PIH 6, 24, and 72 (P0.05), the levels of serum creatinine of rats in burn group at all the time points and hydrogen-rich saline group at the other time points were significantly higher than the level of serum creatinine of rats in sham injury group at PIH 72 (P<0.01). The levels of blood urea nitrogen of rats in burn group and hydrogen-rich saline group at PIH 6, 24, and 72 were significantly higher than the level of blood urea nitrogen of rats in sham injury group at PIH 72 (P<0.01). The levels of serum creatinine and blood urea nitrogen of rats in hydrogen-rich saline group at PIH 6, 24, and 72 were significantly lower than those in burn group at the corresponding time points (P<0.05). (3) There were certain degree of positive expressions of TNF-α, IL-1β, and IL-6 in renal tissue of rats in sham injury group at PIH 72, which were mainly observed in the cytoplasm of renal tubular epithelium cell. The expressions of above-mentioned inflammatory cytokines in renal tissue of rats in burn group at PIH 6, 24, and 72 were higher than those in sham injury group. The expressions of above-mentioned inflammatory cytokines in renal tissue of rats in hydrogen-rich saline group at all the time points were less than those in burn group at the corresponding time points. (4) Compared with those in sham injury group at PIH 72, the mRNA expression levels of TNF-α, IL-1β, and IL-6 of rats in burn group at PIH 6, 24, and 72 were significantly increased (P<0.01). The mRNA expression levels of TNF-α were significantly increased in hydrogen-rich saline group at PIH 6 and 24 (P<0.05 or P<0.01), and the mRNA expression level of IL-6 was significantly increased in hydrogen-rich saline group at PIH 6 (P0.05), and the mRNA expression levels of TNF-α, IL-1β, and IL-6 at the other time points in hydrogen-rich saline group were significantly decreased (P<0.05). (5) Compared with 0.39±0.03 in sham injury group at PIH 72, the protein expression of HMGB1 of rats in burn group at PIH 6, 24, and 72 (1.19±0.07, 1.00±0.06, 0.80±0.05) were significantly increased (P0.05). Compared with those in burn group, the protein expressions of HMGB1 of rats in hydrogen-rich saline group at PIH 6, 24, and 72 were significantly decreased (P<0.05). Conclusions: Hydrogen-rich saline can alleviate the acute kidney injury in severely burned rats through regulating the release of inflammatory cytokines in renal tissue.