Hydrogen gas inhalation ameliorates glomerular enlargement after hypoxic-ischemic insult in asphyxiated piglet model

Acute kidney injury (AKI) has been reported to occur in 30-70% of asphyxiated neonates. Hydrogen (H₂) gas became a major research focus in neonatal medicine after the identification of its robust antioxidative properties. However, the ability of H₂ gas to ameliorate AKI is unknown. We examined histopathological injuries in the piglet renal cortex on day 5 after a hypoxic-ischemic (HI) insult and if H₂ gas can alleviate kidney injuries. Twenty piglets were divided into three groups: no insult (Control, n = 6), HI insult alone (HI, n = 8), and HI insult with H₂ gas ventilation (HI-H₂, 2.1-2.7% for 24 h, n = 6). The total glomerular cell count was significantly higher in the HI group than in the other groups, with no difference between the HI-H₂ and control groups. Proximal tubular lumen narrowing was significantly increased in the HI group versus control, but not in the HI-H₂ group. In this piglet model, glomerular enlargement with an increase in glomerular cell number due to tubular lumen narrowing was observed on day 5 after HI insult. H₂ gas effectively suppressed this glomerular cell increase and tubular lumen narrowing.