AQP4 and brain edema: Currently, the role of Aquaporins (AQPs) in the occurrence and development of cerebral edema is receiving increasing attention, in which AQP4, a water channel protein controlling the entry and exit of water molecules into and out of the cell membrane, has a very important role in the maintenance of water homeostasis of brain tissues, inflammation, and regulation of neural excitability (Miu and Li, 2011).