Methane alleviates sepsis-induced injury by inhibiting pyroptosis and apoptosis: in vivo and in vitro experiments.

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. Methane has been reported to have anti-oxidative, anti-apoptotic and anti-inflammatory properties. We investigated the potential protective effects of methane on sepsis-induced injury and determined the related mechanisms. C57BL/6 mice received laparotomy with cecal ligation and puncture (CLP) to create a septic model, followed by methane-rich saline (MRS) treatment after CLP. MRS treatment improved the 5-day survival rate and organ functions and alleviated pathological damage of the mice, as well as reduced excessive inflammatory mediators, such as tumor necrosis factor-α and interleukin-6. MRS treatment also decreased the levels of oxidative stress index proteins, decreased the apoptosis of cells and inhibited nod-liker receptor protein (NLRP)3-mediated pyroptosis in the lung and intestine. In in vitro experiments, RAW264.7 and primary peritoneal macrophages were treated with lipopolysaccharide (LPS) plus adenosine-triphosphate (ATP) to induce inflammation and pyroptosis. Consistent with the in vivo results, methane-rich medium (MRM) treatment also reduced the levels of excessive inflammatory mediators, and decreased the levels of ROS, inhibited apoptosis and pyroptosis. Our results indicate that methane offers a protective effect for septic mice via its anti-inflammation, anti-oxidation, anti-pyroptosis and anti-apoptosis properties.