Rhubarb Attenuates Cerebral Edema via Inhibition of the Extracellular Signal-regulated Kinase Pathway Following Traumatic Brain Injury in Rats

Background: Rhubarb is a traditional Chinese medicine for treating traumatic brain injury (TBI). Purpose: The purpose of this study is to elucidate the potential mechanism of rhubarb by suppressing extracellular signal-regulated kinase (ERK) to ameliorate brain edema. Materials and Methods: Sprague-Dawley rats were separated into four groups at random. One group received 3 g/kg rhubarb, and another group received 12 g/kg rhubarb, and the vehicle group and sham group were administered the same dose of saline solution. The blood-brain barrier disruption and edema were detected by Evans blue extravasation and water content, respectively. ERK, Matrix metalloproteinase 9 (MMP-9), and zonula occluden-1 (ZO-1) in the damaged tissue were measured by western blot analysis and quantitative real-time polymerase chain reaction. Results: Rhubarb attenuated the brain edema after TBI, especially at the dose of 12 g/kg. Rhubarb significantly suppressed ERK, down-regulated MMP-9, and up-regulated ZO-1. Rhubarb might be a prospective therapeutic regimen to decrease edema in TBI. Conclusions: Rhubarb alleviates the edema by restraining the ERK signaling pathway. Our results contribute to the validation of the traditional use of rhubarb in the treatment of TBI and its mechanism.