TNF and serum lipopolysaccharide activity: The initial phase of endotoxemia involves the polarization of M1-like macrophages and the massive release of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukine-12 (IL-12), and IL-6, as well as free radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS).5