Chronic molecular hydrogen inhalation mitigates short and long-term memory loss in polymicrobial sepsis

• Published in: Brain research 2020-07, Vol.1739, p.146857-146857, Article 146857
• Main Authors: Jesus, Aline A., Passaglia, Patrícia, Santos, Bruna M., Rodrigues-Santos, Isabelle, Flores, Rafael A., Batalhão, Marcelo E., Stabile, Angelita M., Cárnio, Evelin C.
• Format: Article
• Language: English
• Subjects: CLP; Cognition; Learning ability; Memory damage; Oxidative stress
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2020.146857

[Display omitted] •We tested the memory benefits of chronic H2 treatment in CLP-induced sepsis;•Chronic H2 treatment attenuated impaired short and long-term recognition memory in septic rats;•Chronic H2 treatment attenuated impaired learning ability in septic rats;•H2 attenuated impaired long-term associative memory in septic rats;•Acute treatment with H2 attenuated oxidative stress and neuroinflammation. The central nervous system (CNS) is one of the first physiological systems to be affected in sepsis. During the exacerbated systemic inflammatory response at the early stage of sepsis, circulatory inflammatory mediators are able to reach the CNS leading to neuroinflammation and, consequently, long-term impairment in learning and memory formation is observed. The acute treatment with molecular hydrogen (H2) exerts important antioxidative, antiapoptotic, and anti-inflammatory effects in sepsis, but little is known about the mechanism itself and the efficacy of chronic H2 inhalation in sepsis treatment. Thus, we tested two hypotheses. We first hypothesized that chronic H2 inhalation is also an effective therapy to treat memory impairment induced by sepsis. The second hypothesis is that H2 treatment decreases sepsis-induced neuroinflammation in the hippocampus and prefrontal cortex, important areas related to short and long-term memory processing. Our results indicate that (1) chronic exposure of hydrogen gas is a simple, safe and promising therapeutic strategy to prevent memory loss in patients with sepsis and (2) acute H2 inhalation decreases neuroinflammation in memory-related areas and increases total nuclear factor E2-related factor 2 (Nrf2), a transcription factorthat regulates a vast group of antioxidant and inflammatory agents expression in these areas of septic animals.