Figure 7. Expression of immunoreactive AQP4 (green) and glial fibrillary acidic protein (GFAP; red) in the optic nerve of rats exposed to experimentally elevated intraocular pressure. Elevation of IOP was performed as described by Morrison et al [22]. The contralateral (control) eyes showed modest AQP4 and GFAP expression (B-D). In contrast, AQP4 and GFAP labeling at the optic nerve was consistently more intense in eyes exposed to elevated IOP compared to control eyes (F-H). A representative figure of the optic nerve is shown for one rat exposed to >500 mmHg days of IOP elevation. A and E are DIC images, B and F represent AQP4 labeling, C and G represent GFAP labeling, and D and H represent merged images of AQP4 and GFAP labeling (yellow). Scale bars represents 50 μm. Staining was performed without primary antibodies (I-L) that shows no labeling and was used as a negative control.