Hydrogen Gas Reduces Brain Inflammation and Memory Loss in Sepsis
- Authors
- Junia Lara de Deus, Mateus Ramos Amorim, Rui Milton Patricio da Silva Junior, Aline Alves Jesus, Procopio Cleber Gama de Barcellos Filho, Evelin Capellari Carnio, Alexandra Olimpio Siquera Cunha, Ricardo Mauricio Leao, Luiz G.S. Branco
- Journal
- Brain, Behavior, & Immunity - Health
- Year
- 2023
- DOI
- 10.1016/j.bbih.2023.100654
- Study Type
- Rat
- Outcome
- Positive
- Peer Reviewed
- Yes
- Country
- Brazil
- Health Condition
- Sepsis
- Body System
- Nervous System
TL;DR
Inhaling molecular hydrogen (H2) can reduce brain inflammation and memory loss in rats with sepsis-related conditions without affecting their long-term memory formation.
Key Finding
Inhaled hydrogen gas reduced brain inflammation and immune cell activation in the hippocampus during sepsis-like conditions in rats, which was associated with improved memory performance.
Summary
This rat study investigated whether inhaled hydrogen gas could protect memory and reduce brain inflammation during sepsis (a severe, life-threatening infection). Researchers gave rats a bacterial toxin to simulate sepsis, then treated some with hydrogen gas while measuring inflammation markers and memory performance. Inhaled hydrogen reduced inflammatory chemicals in the brain, calmed immune cells in the hippocampus (the memory center), and improved memory performance compared to untreated rats.
Practical Takeaway
This early-stage rat study suggests hydrogen gas may have protective effects on memory during severe infection, but it is far too preliminary to draw conclusions for humans. Sepsis-associated cognitive problems are a real clinical concern, and this research identifies a potential mechanism worth further investigation—but human studies would be needed before any therapeutic recommendations could be made.
Abstract
Sepsis is associated with numerous physiological and biochemical abnormalities that result in a life-threatening condition. The involvement of the Central Nervous System (CNS) during sepsis has received considerable attention, especially the hippocampus which plays a key role in the learning and memory processes. The increased interest in this limbic region during systemic inflammation (SI) is related to the number of sepsis survivor patients who have cognitive impairments. A single injection of lipopolysaccharide (LPS)-induced systemic inflammation is the most commonly used murine endotoxemia model because it replicates several pathophysiological changes observed in severe sepsis. Molecular hydrogen (H2) has been used as an anti-inflammatory therapeutic strategy to prevent neuroinflammation. However, the mechanisms by which inhaled H2 mitigate memory loss during SI remains unknown. To understand how H2 acts in the hippocampus, the current study focused on specific mechanisms that may be involved in reducing neuroinflammation in rats during SI. We hypothesized that inhaled H2 decreases LPS-induced hippocampal pro-inflammatory cytokines surges and this effect is associated with reduced memory loss. Using different and integrative approaches, i.e., from hippocampal cells electrophysiology to animal behavior, we report that inhaled H2 decreased LPS-induced peripheral and hippocampal inflammation, decreased microglial and astrocytic activation, lessen memory loss without affecting long-term potentiation (LTP). To our knowledge, this is the first evidence showing that inhaled H2 reduces hippocampal microglial and glial cells inflammation, which may be associated with a reduced memory impairment induced by SI.