The effect of AQP4 gene on the activation of retinal glial cells in chronic high intraocular pressure mice

Abstract

To investigate whether aquaporin 4 (AQP4) gene can affect the activation of glial cells and cause the injury of retina of chronic high intraocular pressure mice models, and to discuss its possible mechanism. Experimental study. The chronic high intraocular pressure models were established by burning the scleral venous of the right eye, which as the experiment group, and the left eye without any treatment as the control group. The intraocular pressure (IOP) was measured by rebound tonometer. Selected each of the successful model of chronic high intraocular pressure male AQP4 knockout mice (AQP-/-) and their wild-type (WT) male mice 40, divided the two type of mice into five groups after scleral venous burn according to the time of establishing models (24 h, 3 d, 1 w, 2 w, 4 w after scleral venous burn), 8 mouse in each group. And then producing the paraffin sections of mouse eye. Immunohistochemical staining methods was used to observe the expression of the glial fibrillary acid protein (GFAP) in retina glial cells, and observe the expression of the AQP4 in the retina of the WT mouse. Image was acquired under the fluorescence microscopy. The intraocular pressure was analyzed by t-test. After scleral venous burn (24 h, 3 d, 1 w, 2 w, 4 w), there were significant difference (t = 6.66 - 18.08, all P value < 0.05) in the IOP of the AQP4-/- mice (11.30 ± 1.59, 11.20 ± 1.15, 10.60 ± 1.53, 10.75 ± 1.45, 10.45 ± 1.39) and WT mice (11.50 ± 2.56, 11.25 ± 1.65, 10.75 ± 1.33, 10.60 ± 1.33, 10.40 ± 1.19) between the experimental groups and control groups (6.60 ± 0.94, 6.35 ± 0.99, 6.55 ± 0.94, 6.45 ± 0.99, 6.50 ± 0.94 and 6.60 ± 1.05, 6.50 ± 0.89, 6.40 ± 1.09, 6.30 ± 1.13, 6.50 ± 1.05). Since 24 hours after the scleral venous burn, the expression of GAFP of the two type mice began to increase and reached to peak at 1 week after burning. This peak of WT mice was more obvious than that of AQP4-/- mice. The concentration of GAFP began to decrease at 2 weeks after burning and reached to bottom at 4 weeks later. To the WT mice, the expression of AQP4 was remarkable higher in experimental group than that in control group at 1 week after the scleral venous burn. The expression of AQP4 was related to the expression of GAFP in high intraocular pressure of WT mice at 1 w, 2 w, and 4 w after the scleral venous burn. The chronic high intraocular pressure models can be established successfully by burning the scleral venous. AQP4 gene can affect the activation of the glial cells in chronic high intraocular pressure mice and lead to the injury of retina.