Another study by Niantiarno et al. (9) on the expression of aquaporin-4 (AQP4) as a water channel protein and a key regulator of water metabolism in the brain found that the intensity of AQP4 increased in rats with traumatic brain injury, and this expression decreased after treatment with Kaempferia galanga L. ethanolic extract at a dose of 1,200 mg/kgBW/day within 24 h and 48 h. This evidence concerns the gene AQP4 and brain injury.