Yan Li et al. [18] found that emodin improved the neurological deficit scores (NDS), reduced BBB permeability, and decreased the infarction area in cerebral ischemia/reperfusion (I/R) model rats; these results were probably due to the inhibitory effect of emodin against the expressions of connexin 43 (Cx43) and aquaporin 4 (AQP4). This evidence concerns the gene AQP4 and brain ischemia.