HMOX1 and cerebral artery occlusion: Andrographolide enhances HO-1 expression in primary brain endothelial cells and rat brain tissue by regulating the p38 MAPK-Nrf2-HO-1 cascade; in a study of a rat model of middle cerebral artery occlusion, andrographolide enhanced HO-1 expression by decreasing the production of free radicals in brain tissue and reducing brain oedema and infarct area to mitigate brain injury in rats with middle cerebral artery occlusion (Yen et al., 2016).