Methane Limit LPS-induced NF-κB/MAPKs Signal in Macrophages and Suppress Immune Response in Mice by Enhancing PI3K/AKT/GSK-3β-mediated IL-10 Expression

Inflammatory diseases such as sepsis and autoimmune colitis, characterized by an overwhelming activation of the immune system and the counteracting anti-inflammatory response, remain a major health problem in worldwide. Emerging evidence suggests that methane have a protective effect on many animal models, like ischaemia reperfusion injury and diabetes-associated diseases. Whether methane could modulating inflammatory diseases remains largely unknown. Here we show that methane-rich saline (MS) ip treatment (16 ml/kg) alleviated endotoxin shock, bacteria-induced sepsis and dextran-sulfate-sodium-induced colitis in mice via decreased production of TNF-α and IL-6. In MS-treated macrophages, LPS-induced activation of NF-κb/MAPKs was attenuated. Interestingly, MS treatment significantly elevated the levels of IL-10 both in vitro and in vivo. Neutralization of IL-10 abrogated the therapeutic effect of MS. Moreover, anti-IL10 blockade partially restored the MS-mediated attenuation of NF-κb/MAPKs phosphorylation. We further found that MS resulted in markedly enhanced phosphorylation of GSK-3β and AKT, which both mediate the release of Il-10. Additionally, inhibition of PI3K attenuated MS-mediated p-GSK-3β and IL-10 production and reversed the suppressed activation of NF-κb/ MAPKs in response to LPS. Our results reveal a novel effect and mechanisms of methane and support the potential value of MS as a therapeutic approach in innate inflammatory diseases.