Anti-Inflammation Effects Of Hydrogen Saline On Paw Oedema Induced By Carrageenan

Background: Oxidative stress is thought to play an important role in the pathogenesis of inflammation not only through direct injurious effects, but also by involvement in the molecular mechanism. Among the complex factors involved in the process of inflammation, reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as the hydroxyl radical (?OH), superoxide anion (O2–), hydrogen dioxide (H2O2), nitric oxide (NO), peroxynitrite (ONOO–), appear to be critical elements. There is a large amount of evidence to show that Inhibitors of NOS activity reduce the severity of inflammation. It has been reported recently that H2 selectively reduced ?OH and ONOO– . So, as a free radical scavenger, H2 may have the effect of anti-inflammation. However, inhalation of hydrogen gas may be not convenient for therapeutic use,so we dissolved molecular hydrogen (H2) in saline under high pressure (0.6MPa), and examine the effects of hydrogen saline on inflammation models.Methods: The severity of inflammation damage was evaluated by paw volume measurement and inflammatory cells infiltration. TNF-αin supernatants was evaluated by ELISA. RT-PCR was used to characterize the mRNA expression of TNF-αin RAW264.7 macrophages.Results: Hydrogen saline showed dose dependently down-regulated carrageenan-induced paw swelling, compared with the vehicle control group, which received an equal volume of vehicle only (saline). The treatment of animals with hydrogen saline produced a significant decrease in the number of infiltration neutrophils in the inflammatory paw.Supernantant TNF-αlevel from activated macrophages (collected 4h after LPS stimulation) treated with saline were significantly higher than that treated with hydrogen saline. This result was similar in both murine peritoneal macrophages and RAW 264.7 murine macrophages which indicated that hydrogen saline has the ability to inhibit TNF-αproduction of macrophages. Expression of activated macrophage mRNA was determined 1hr after the treatment of hydrogen saline or saline. Results were expressed as the ratio of mRNA cytokine/mRNA microglobin. TNF-αmRNA of activated macrophages treated with hydrogen saline was lower than that treated with saline.Conclusions: Our findings indicate that the hydrogen saline had the effect of anti-inflammation in both the paw oedema models and LPS-activated macrophages. The possible mechanism may work by reducing ?OH and ONOO–. So we could conclude that hydrogen saline may be a potential candidate for the therapy of inflammatory diseases, which is more convenient to be administered than inhaling hydrogen.