TNF and memory impairment: Several in vitro and in vivo studies have demonstrated that the systemic administration of LPS causes the activation of ROS and activated glial cells (astrocytes and microglial cells), the elevation of cytokines including TNF-α, intracellular adhesion molecule-1, and IL-6, as well as the increase of inflammatory proteins, such as inducible nitric oxide synthase and cyclooxygenase-2, which are factors known to be responsible for neuroinflammatory disorders and lead to memory impairments [35,36].