TNF and acute respiratory distress syndrome: In a rat model of ALI induced by occlusion/reperfusion of the superior mesenteric artery, intravenous treatment by rat bone marrow MSC-derived exosomes attenuated lung damage by decreasing apoptosis and the pulmonary levels of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β, accompanied by a downregulation of the expressions of TLR4 and NF-κB (288).