Six Hours of Hydrogen Gas Inhalation Has a Neuroprotective Effect Even in Piglets with Delayed Functional Recovery

Area of Science:

• Neuroscience
• Neonatal Research
• Biomedical Engineering

Background:

• Hypoxic-ischemic (HI) injury is a major cause of neonatal brain damage.
• Therapeutic hypothermia (TH) is a standard treatment, but its efficacy can be limited.
• The neuroprotective potential of hydrogen (H₂) gas in the acute phase of HI injury requires further investigation.

Purpose of the Study:

• To investigate the neuroprotective effects of early H₂ gas inhalation following HI insult in a neonatal piglet model.
• To assess the impact of H₂ gas on neuronal survival and early electroencephalogram (EEG) recovery.

Main Methods:

• Seventeen piglets aged ≤24 hours underwent HI insult.
• Piglets were randomized into two groups: HI insult only (n=8) and HI with 6-hour H₂ gas inhalation (2.1%-2.7%) starting at resuscitation (n=9).
• Time to recovery of normal amplitude-integrated EEG background (RT-aEEG) and undamaged neuron counts were evaluated.

Main Results:

• No significant difference in the duration of low-amplitude EEG (<5 μV) was observed between the HI and HI-H₂ groups.
• The HI-H₂ group exhibited a significantly higher number of undamaged neurons compared to the HI group (p < 0.01).
• Despite increased neuronal survival, RT-aEEG did not differ between groups.

Conclusions:

• Six hours of H₂ gas inhalation initiated immediately after resuscitation provides significant neuroprotection by increasing neuronal survival in piglets with HI injury.
• H₂ gas demonstrates a neuroprotective effect even when early functional recovery, as measured by RT-aEEG, is delayed.
• Early H₂ gas administration is a promising therapeutic strategy for mitigating brain damage after neonatal HI insult.