Purpose: To investigate whether retinal impairment was affected by age of rats in acute glaucoma model.
Methods: Young adult and aged rats were randomly divided into normal control, 45 mmHg, 60 mmHg and 90 mmHg groups. Intraocular pressures (IOP) of rats were acutely elevated to 45 mmHg, 60 mmHg and 90 mmHg, respectively. Neuron loss in ganglion cell layer (GCL) and activation of retinal macrolgia and microglia 3 days after high IOP treatment were detected by immunofluorescence and further quantitatively analyzed.
Results: Compared with normal control, significant loss of neurons at GCL of young adult retina wasn't detected until IOP treatment of 90 mmHg. In contrast, obvious loss of neurons at GCL of aged retina was detected at IOP of 45 mmHg (p = 0.002 for central; p = 0.001 for peripheral). The loss level of neurons of aged retina was significantly higher than that of young adult retina at different IOP treatments. Compared with the young adult retina, high IOP induced more significant increase at area percentage of microglia and microglia number in inner part of aged retina. Activation of microglia and macroglia was either in parallel to or earlier than neuron loss of GCL of aged and young adult retina.
Conclusion: Our data suggest there exists an age-related susceptibility of rat retina to the increased IOP. Therefore, the effect of ages should be considered at glaucoma study of rat models.
Keywords: Aging; glaucoma; intraocular pressures; rat; retina.