Expression of aquaporin 4 in 1,2-dichloroethane-induced toxic brain edema in rats / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the effects of aquaporin 4( APQ4) in rat toxic brain edema induced by subacute 1,2-dichloroethane( 1,2-DCE) exposure. METHODS: Thirty-two specific pathogen free healthy adult female SD rats were randomly divided into control( 8 rats),low-dose( 12 rats) and high-dose( 12 rats) groups. The treatment groups were exposed to 1,2-DCE( low-dose 600 mg / m3; high-dose 1 800 mg/m3,nose-only) and the control group was exposed to fresh air by dynamic inhalation for 8 hours per day for consecutive 7 days. After exposure,histopathologic changes were examined in the cerebral cortex. Real-time polymerase chain reaction was used to detect the mRNA relative expression of matrix metalloproteinase 2( MMP2),Na-K-Cl cotransporter-1( NKCC1) and AQP4. The Western blotting was used to detect the expression of AQP4 protein in the cerebral cortex. RESULTS: The pathological results showed that the cerebral cortex tissues were loose around the peripheral vessels and the vessels tissue space appeared widen in low-dose exposure group. The pathological change was more serious in high-dose group than low-dose group,with obvious loosen vessels and vacuole. Compared with those of the control group and the low-dose group,the relative expression level of MMP2 mRNA in the high-dose group increased significantly[( 1. 07 ± 0. 41) vs( 1. 56 ± 0. 55),( 1. 21 ± 0. 59) vs( 1. 56 ± 0. 55),P <0. 05],while the the relative expression level of AQP4 mRNA in the high-dose group significantly decreased [( 1. 03 ±0. 25) vs( 0. 81 ± 0. 12),( 1. 00 ± 0. 20) vs( 0. 81 ± 0. 12),P < 0. 05]. The relative expression levels of NKCC1 mRNA in all groups showed no statistical difference [( 1. 03 ± 0. 31) vs( 1. 14 ± 0. 43) vs( 1. 36 ± 0. 50),P > 0. 05]. The relative expression level of AQP4 protein in the high-dose group was lower than that of the control group [( 0. 80 ± 0. 25) vs( 1. 19 ± 0. 42),P < 0. 05]. CONCLUSION: The brain edema induced by subacute inhalation of 1,2-DCE is of mixed types with vasogenic edema as its main symptom. Its pathogenesis is related to the changes of AQP4 expression.