Riluzole- and Resveratrol-Induced Delay of Retinal Ganglion Cell Death in an Experimental Model of Glaucoma

<div><p></p><p><i>Purpose</i>: To evaluate the effects of the neuroprotective agents riluzole and resveratrol on the survival of retinal ganglion cells (RGCs) when administered alone or in combination.</p><p><i>Materials and methods</i>: Experimental glaucoma was induced by injecting hyaluronic acid into the anterior chamber of Wistar albino rats weekly for a six-week period. Intraocular pressure was measured before and immediately after glaucoma induction. The neuroprotective effects of daily intraperitoneal injections of riluzole (8 mg/kg) and resveratrol (10 mg/kg) were evaluated and compared. After the six-week period, dextran tetramethylrhodamine was applied into the optic nerve and the density of surviving RGCs was evaluated by counting the labeled RGCs in whole mount retinas for retrograde labeling of RGCs.</p><p><i>Results</i>: The mean numbers of RGCs were significantly preserved in all treatment groups compared to the vehicle-treated glaucoma group (G). The mean number of RGCs in mm² were 1207 ± 56 in the control group (C), 404 ± 65 in G group, 965 ± 56 in riluzole-treated group in the early phase of glaucoma (E-Ri), 714 ± 25 in riluzole-treated group in the late phase of glaucoma (L-Ri), 735 ± 29 in resveratrol-treated group in the early phase of glaucoma (E-Re), 667 ± 20 in resveratrol-treated group in the late phase of glaucoma (L-Re), and 1071 ± 49 in riluzole and resveratrol combined-treated group in the early phase of glaucoma (E-RiRe group).</p><p><i>Conclusions</i>: When used either alone or in combination, both riluzole and resveratrol, two agents with different mechanisms of action in glaucoma, significantly delayed RGC loss in this study’s experimental glaucoma model.</p></div

The Effect of Everolimus on Scar Formation in Glaucoma Filtering Surgery in a Rabbit Model

<p><i>Purpose</i>: To investigate the efficiency of everolimus on the prevention of postoperative scar in a rabbit model of glaucoma filtering surgery in comparison with mitomycin-C (MMC).<i>Materials and Methods</i>: Thirty New Zealand albino rabbits were randomly assigned into 3 groups, each including ten rabbits: an everolimus group (Group 1), a MMC group (Group 2), and a sham group (Group 3). A limbal-based trabeculectomy was performed on the right eyes of all the rabbits. For 28 days following surgery, the eyes were evaluated in terms of intraocular pressure (IOP), morphological and biomicroscopic changes, and complications in the bleb. On the 28th day, four eyes randomized from each group were enucleated and histologically and immunohistochemically analyzed. Transforming growth factor-β1 (TGF-β1), metalloproteinase (MMP-2, MMP-9), and proliferative cell nuclear antigen (PCNA) expressions in each group were evaluated. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used for apoptosis.<i>Results</i>: Bleb survival was statistically significantly longer for a period in Group 1 compared to Group 2. When postoperative IOPs of three groups were measured, it was seen that there is significant IOP reduction in all three groups. However, there were increases in the mean IOP values beginning from the 5th day in Group 2 and from the 3rd day in Group 3 while in Group 1 mean IOP values began to increase beginning from 10th day and the mean IOP values in Group 1 remained at a lower level in comparison to the other groups for 28 days (<i>p</i> < 0.05). The expressions of TGF-β1, MMP-2, MMP-9, and PCNA were reduced in Group 1 compared to other groups. TUNEL positive apoptotic cells were significantly increased in Group 1 compared to other groups (<i>p</i> < 0.05).<i>Conclusion</i>: Everolimus appears to suppress the proliferation of fibroblast and thus may provide an effective treatment strategy in glaucoma filtering surgery.</p