Differential Changes of Local Blood Supply in Rat Retinae Are Involved in the Selective Loss of Retinal Ganglion Cells Following the Acute High Intraocular Pressure

Purpose: To detect changes in local blood supply to central, middle, and peripheral retina following acute high intraocular pressure and to investigate the effects of changes in local retinal blood supply on the selective loss of retinal ganglion cells. Methods: The acute high intraocular pressure model of Sprague-Dawley rats was established by increasing the anterior chamber pressure to 110 mmHg via a normal saline perfusion system. Blood supply to the central, middle, and peripheral retina at 3, 6, and 12 h, and 1, 3, 7, and 14 d following induction of acute high intraocular pressure was detected by using gelatin-ink perfusion and fluorescent microsphere injection. Retinal ganglion cell loss following acute high intraocular pressure was detected by fluorogold retrograde labeling. Finally, the relationship between changes in local retinal blood supply and loss of retinal ganglion cells was investigated. Results: The increased ratio of blood supply of peripheral retina was less than that of the central and middle retina at 3 h to 14 d following acute high intraocular pressure. The percent of retinal ganglion cell loss in the peripheral retina was clearly greater than that in the central and middle retina during the first 3 d following induction of acute high intraocular pressure (p<0.05). Using either the gelatin-ink infusion method or the microsphere injection method (p<0.05), a significantly negative correlation between the percent of retinal ganglion cell loss and the corresponding increased local blood supply after induction of acute high intraocular pressure (r = -0.57 or -0.72) was found. Moreover, a significant negative correlation in the peripheral retina (r = -0.80 or -0.91; p<0.05) was observed. Conclusion: A disparity exists between changes in local blood supply to the central and middle retina, and the peripheral retina following induction of acute high intraocular pressure in rats. This inequality of changes in local blood supply in rat retina is related to the selective loss of retinal ganglion cells.