| Objective:The present study was to research the changes and effects of AQP4 and BBB permeability in traumatic cerebra edema by establish the models of frontal lobe contusion in rats. And we try to explore the mechanism that why progesterone can soften brain water content in traumatic brain edema.Methods:The models of focal lobe contusion and laceration of brain were maded.108 male healthy Sprague-Dawley adult rats, all were subjected into three groups by randomly:Sham-operated,Injured -control group,PROG-test group, the control group and the test group were devided into four subset group by time,which named 6h, 24h, 72h, 120h group.PROG-test group were given 16 mg/kg injections of progesterone and the injured-control group were accepted equal volumes of 0.9%isotonic Na chloride per-12hours following injury, progesterone or 0.9%isotonic Na chloride was injected into the abdominal cavity of the rats. Brain tissues were extracted at 6, 24, 72 and 120 h post-injury, HE staining was performed for morphologic change by light microscope,immunohistochemical method was measured to assess the express- ion of aquaporin-4 (AQP4), Evan's Blue method was investigated to detect the permeability of blood-brain barrier, dry-wet wei- ght method was measured to evaluate the cerebral water content.Results:1.The lower expression of AQP4 took place on astrocytes of the contusion and peri-contusion of the brain tissue at 6h post- injury, compared with the sham-operated group, (P<0.01) while up-regurated at 24h,72h,120h and especially at 72h post-injury .2. The content of EB in the contusion and peri-contusion brain area were higher measured in both controled and test group compared with the sham group(P<0.01), especially at 6h post- injured ,and then decreased slowly. 3.Brain edema content were higher at 6h and were highest at 72h post-injured. In both controled and test group ,the brain water content was higher than Sham group(P<0.05).4. The straight line correlation analysis indicated that there was a significant positive correlation between the expression of AQP4 and the change of the water content of brain tissue following TBI. the Pearson coefficient: r=0.506 ,P<0.05. 5.The straight line correlation analysis indicated that there was a significant negative correlation between the expression of AQP4 and the change of the permeability of blood-brain barrier following TBI. the Pearson coefficient: r=-0.79, P<0.01.6. The expression of AQP4 in frontal lobe contusion decreased respectively at 24h,72h and 120h after progesterone administration,there was significant difference(P<0.01),which demonstrated that prog- esterone administration could mitigate the brain injury by inh- ibiting the expression of AQP4;The content of EB in frontal lobe contusion descensused respectively and significant difference at 6h and 24h after progesterone intervention, (P<0.05);The water content of brain tissue decreased respectively at 6h,24h,72 and 120h after progesterone injection,there was significant difference(P<0.05).Conclusions:1.AQP4 participated the truamatic brain edema after focal frontal lobe contusion in rats.2.Perhaps the damage of the astrocyte foot process on the blood-brain barrier is the main reason for the AQP4 decreased early after focal frontal lobe contusion in rats. 3.Progesterone can soften the traumatic brain water conte- nt may associated with the attenuate of AQP4 in frontal lobe contusion following TBI and protect the blood-brain barrier at a early time.
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