Abstract: Objective To study the effect of thyrotrophin releasing hormone (TRH) analogue, YM14673, on the brain edema and blood brain barrier after brain injury in rat.Methods The model of brain injury of rats was built by Feeney's methods. The Evans blue solution had been injected i.v. into the rats before the models were made. The rats were divided into four groups: normal, treated with saline, treated with YM14673(Ⅰ:0.1mg/kg and Ⅱ:1mg/kg). The water content in brain was measured 24 h after brain injured. The concentration of Evans blue in brain tissue and blood was measured with fluorometry.Results The rats treated with saline after traumatic injury showed significantly high water content compared with normal group(P<0.01)and the water content of the left hemisphere, which was hit straightly, was higher significantly than that of the right global(P<0.01). The brain water content decreased in the rats treated with YM14673 in all global(P<0.05).There was no significant different between the treated group Ⅰ and groupⅡ.After brain injury, the concentration of Evans blue in brain tissue showed a higher level contrasted with normal group. YM14673 did not influence the concentration of Evans blue in brain tissue. Conclusion YM14673 can decrease the brain edema after brain injury but it cannot decrease the permeability of blood brain barrier.

Key words: thyrotrophin-releasing hormone (TRH), YM14673, brain trauma, blood-brain barrier, brain edema