Hydrogen Gas Protects Lungs from Oxygen Damage in Critical Care
- Authors
- Tomohiro Kawamura, Nobunao Wakabayashi, Norihisa Shigemura, Chien-Sheng Huang, Kosuke Masutani, Yugo Tanaka, Kentaro Noda, Ximei Peng, Toru Takahashi, Timothy R. Billiar, Meinoshin Okumura, Yoshiya Toyoda, Thomas W. Kensler, Atsunori Nakao
- Journal
- American Journal of Physiology-Lung Cellular and Molecular Physiology
- Year
- 2013
- DOI
- 10.1152/ajplung.00164.2012
- Study Type
- Rat
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- United States
- Health Condition
- Hyperoxic Lung Injury
- Body System
- Respiratory
TL;DR
Breathing in hydrogen gas can help reduce lung damage caused by high levels of oxygen in critically ill patients, through a protective mechanism that involves specific genes.
Key Finding
Inhaled hydrogen gas significantly reduced lung damage from high oxygen exposure in rats by activating a protective pathway involving the Nrf2 protein and heme oxygenase-1.
Summary
Researchers exposed rats to high concentrations of oxygen (which can damage the lungs) and tested whether inhaled hydrogen gas could help protect against this injury. Rats that received hydrogen along with high oxygen showed better blood oxygen levels, less inflammation, and activation of a protective protein called heme oxygenase-1. When researchers tested this in mice lacking a key protein called Nrf2, hydrogen no longer provided protection, showing that this protein is essential for hydrogen's protective effect.
Practical Takeaway
This animal study suggests hydrogen gas may have potential as a medical treatment for oxygen-related lung injury in critically ill patients, though human studies would be needed to determine if these results apply to people. The findings are limited to laboratory rats and do not yet indicate whether hydrogen water (consumed orally) would have similar effects.
Abstract
Hyperoxic lung injury is a major concern in critically ill patients who receive high concentrations of oxygen to treat lung diseases. Successful abrogation of hyperoxic lung injury would have a huge impact on respiratory and critical care medicine. Hydrogen can be administered as a therapeutic medical gas. We recently demonstrated that inhaled hydrogen reduced transplant-induced lung injury and induced heme oxygenase (HO)-1. To determine whether hydrogen could reduce hyperoxic lung injury and investigate the underlying mechanisms, we randomly assigned rats to 4 experimental groups and administered the following gas mixtures for 60 hours: 98% oxygen (hyperoxia), 2% nitrogen; 98% oxygen (hyperoxia), 2% hydrogen; 98% balanced air (normoxia), 2% nitrogen; and 98% balanced air (normoxia), 2% hydrogen. We examined lung function by blood gas analysis, extent of lung injury, and expression of HO-1. We also investigated the role of NF-E2-related factor (Nrf) 2, which regulates HO-1 expression, by examining the expression of Nrf2-dependent genes and the ability of hydrogen to reduce hyperoxic lung injury in Nrf2-deficient mice. Hydrogen treatment during exposure to hyperoxia significantly improved blood oxygenation, reduced inflammatory events, and induced HO-1 expression. Hydrogen did not mitigate hyperoxic lung injury or induce HO-1 in Nrf2-deficient mice. These findings indicate that hydrogen gas can ameliorate hyperoxic lung injury through induction of Nrf2-dependent genes, such as HO-1. The findings suggest a potentially novel and applicable solution to hyperoxic lung injury, and provide new insight into the molecular mechanisms and actions of hydrogen.