Emodin Attenuates Brain Edema After Traumatic Brain Injury In Rats

Background: Emodin, a major component extract of Rhizoma Polygoni Cuspidati, has various biological activities. The current study was to investigate the effects of emodin on brain edema after traumatic brain injury (TBI) in rats. Material and methods: Rat model of traumatic brain injury was established using Modified Feeney method, then rats were treated with emodin (10 mg/kg) 30 min before TBI and given once daily during the experiments. After neurological severity scores (NSS) evaluation at 1, 2 and 7 days, the animals were sacrificed. Brain samples were obtained and used for brain water content and blood-brain barrier (BBB) permeability measurement, as well as RT-PCR and Western blots. Results: Emodin significantly improved neurological function, reduced BBB permeability and ameliorated brain edema after TBI. It inhibited the expression of aquaporins (AQPs), including AQP-1, AQP-4 and AQP-9 both in mRNA and protein levels. Additionally, increased hypoxia-inducible factor-1 alpha (HIF-1 alpha) and matrix metalloprotein-9 (MMP-9) levels-induced by TBI were diminished after the treatment of emodin. Conclusion: Our results suggest that emodin exhibits neural protective effect on brain edema after TBI and the molecular mechanism is probably associated with the suppression of HIF-1 alpha/AQPs and HIF-1 alpha/MMP9 pathways.