Changes Of Aqp4 Expression In Experimental Ischemic Brain Edema And The Intervension Study Of Aprotinin

Object: The aim of the study is to investigate the relationship between AQP4 and ischemic brain edema through developing observing the change of AQP4 of rats MCAO model. We try to find out the formation mechanisms of ischemic brain edema and clarify the action of AQP4 in the formation of brain edema. Evaluate the anti-action of Aprotinin in ischemic brain edema. Methods: We established the experimental ischemic brain edema model by line-lock using health Wistar rats in the study. We estimate the markers as immune expression intensity of AQP4, brain water content ,ion content, IL-8　at different time(6h,12h,24h,48h,72h,120h)after MCAO and compare the markers between Aprotinin group and saline control group. Results: 1. AQP4 resides in cytomembrane of the cell around cerebral vessels and the epithelial cell of cerebral ventricle choroids plexus. It also express in the ependymal cell.2. The immune expression of AQP4 reinforce after MCAO. The relationship between the level of immune expression reinforcement of AQP-4after ischemia and the change of brain water content and ion content is parallel. The changes were present at 6 hour and the peak present during 48～ 72 hour.3. The level of brain water content ,IL-8 content ,AQP4 immune expression intensity was decreased and ion content disorder was improved after Aprotinin administration. Conclusion: 1. Immune expression intensity of AQP4 related with the level of ischemic brain edema. The relationship between immune expression reinforcement of AQP4 after brain ischemia and brain edema is direct ratio.2. AQP4 may play a role in the formation of brain edema .The change of its function or structure would affect the cell membrane permeability and the water distribution. The alteration of AQP4 expression would change the water equilibrium state in brain.3. Aprotinin could Inhibit ischemic brain edema .The mechanism is that it inhibits Kallikrein and decreased the level of Bradykinin. It also inhibits some cytokine and relieves inflammatory reaction. Aprotinin may inhibit the expression of AQP4 so that active transport of water is regulated and the cell membran permeability is decreased to prevent or relieve brain edema.KEY WORDS: Ischemic brain edema ; Aprotinin ; AQP4...