[Research on acting mechanism of rhubarb on aquaporin-4 in rats with blood-brain barrier injury after acute cerebral hemorrhage].

Abstract

OBJECTIVE: To investigate the mechanism of rhubarb in regulating aquaporin-4 in rats with blood-brain barrier damage after acute cerebral hemorrhage (CH). METHODS: CH model was induced by stereospecific injection of auto-blood into caudate nucleus of rats, and the brain water content and neurological defect were detected to evaluate cerebral edema and neurological defect level. Also, the blood-brain barrier damage was observed by Evan's blue staining; the changes of blood-brain barrier tight junction and astrocyte end feet at different time points were observed with electron microscope; and the AQP-4 mRNA and protein expression were measured with RT-PCR and Western blot. RESULTS: Rhubarb showed effects in reducing cerebral edema. Evan's blue result indicated the blood-brain barrier was evidently damaged at the 12th hour after CH, with blood-brain barrier tight junction damaged and astrocyte end feet process swelled obviously, but these changes could be relieved by rhubarb. The AQP-4 mRNA and protein expression in rats increased significantly 24 hrs after modeling (P < 0.05) and reached the peak value at 72 hrs, and decreased gradually after then. Rhubarb also showed inhibiting transcription and translation of AQP-4 gene. CONCLUSION: Rhubarb could alleviate cerebral edema via reducing blood-brain barrier tight junction damage and astrocyte end feet process swelling, which might be realized by the inhibition on transcription and translation of AQP-4 gene.