AQP4 and brain edema: To maintain the water balance in the central nervous system, AQP4 mainly processes water uptake and water transfer at the end foot of astrocytes.[7] Although the related research is still limited, it is clear that the abnormal expression of AQP4 in brain astrocytes is closely related to cerebral edema formation.[8] It is noteworthy that the cellular composition of the spinal cord is similar to that of the brain, and the pathogenesis of edema in SCII is similar to that of brain edema.