Objective: To observe the expression of aquaporin-4 (AQP-4) mRNA and study the relationship between AQP-4, brain edema, pathological changes and ultrastructure of peri-hematoma tissue in intracerebral hemorrhage (ICH) patients.
Methods: Intracranial operation was performed via nonfunctional area with a funnel-like approach on 30 ICH patients. The brain tissue which must be removed 1 cm away the hematoma was removed within 12 hours for observation as normal brain tissue and taken as the control group (7 patients), and which of the brain tissue within 1 cm around hematoma was taken as the study specimens. The experimental group was subdivided into five groups according to the time interval after ICH: <6 hours (6 cases), 6-12 hours (7 cases), 12-24 hours (5 cases), 24-72 hours (6 cases), and >72 hours ( 6 cases ). Expression of the AQP-4 mRNA, brain edema, pathological and ultrastructural changes were observed with reverse transcription-polymerase chain reaction (RT-PCR), light microscope and electron microscope.
Results: The expression of the AQP-4 mRNA was not remarkable, the morphology and construction were basically normal in control group. The expression of AQP-4 mRNA was mild (1.17+/-0.41)and there was edema of neuroglia in the <6 hours group. After 6 hours, besides neuroglial edema, the expression of the AQP-4 mRNA was gradually obvious, capillary endothelial cells began to swell too, and tight junctions gradually began to loosen. In the 12-72 hours group the expression of the AQP-4 mRNA reached its peak (3.50+/-0.55, 3.60+/-0.55, both P<0.01), and brain edema was most prominent, and electron microscopy showed that neurons, neuroglia, and capillary endothelial cells were markedly deformed. After 72 hours, the expression of AQP-4 mRNA gradually recovered, and brain cells showed less damage. On the 5th day the damage began to repair, and on the 8th day, the damage was basically repaired. The correlation analysis showed that there was a remarkable positive correlation between the expression of the AQP-4 mRNA and the degree of brain edema and the size of hematoma (r(1)=0.67, P<0.01; r(2)=0.44, P<0.05) .
Conclusion: Secondary edema and brain damage may correlate with the expression of the AQP-4 mRNA in the peri-hematoma brain edema area. Removal of hematoma will help decrease the AQP-4 mRNA expression and brain edema damage in the early stage.