“…BBB impairment by METH has been reviewed in several mechanisms, including the hyperactivity of NADPH oxidase (NOX)-2 which generates excessive amounts of free radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS) (Ramirez et al, 2009;Park et al, 2012); the dysfunction of cytoskeleton and the trans-membrane protein of tight junction, which is the controlling of paracellular permeability (Park et al, 2013;Fernandes et al, 2015); the dysfunction of the uptake and the efflux activities (ElAli et al, 2012); and the activation of caspase cascade in cell death response or apoptosis (Abdul-Muneer et al, 2011;Ma et al, 2014;Fisehr et al, 2015). Moreover, overexpression of inflammatory mediators such as inducible nitric oxide synthase (iNOS), nitric oxide (NO), interleukin (IL)-1, and tumor necrosis factor (TNF), which is an important factor in inflammatory response, has also been reported (Fernandes et al, 2014;CoelhoSantos et al, 2015;Parikh et al, 2015;Zhang et al, 2015;Skaper et al, 2014;Husain et al, 2015;Kothur et al, 2015). Previous studies have demonstrated that the release of cytokines causes progressive BBB impairment by the upregulation of leukocyte-endothelial cell adhesion molecules such as intercellular adhesion molecules (ICAM)-1, vascular cell adhesion molecules (VCAM)-1, and matrix metallopeptidase (MMP)-9 leads to tight junction impairment (Urrutia et al, 2013;Fernandes et al, 2014;Wang et al, 2014aWang et al, , 2014bParikh et al, 2015).…”