Kazuhiro Iwamoto

Doctoral Dissertation Announcement

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Candidate: Kazuhiro Iwamoto

Degree of: Doctor of Philosophy

Department: Biological Sciences

Title: Neuroprotective Effects of a Nicotinic Acetylcholine Receptor Agonist and Modulator in the Rodent Retina

Committee:
Dr. Cindy Linn, Chair
Dr. John Jellies
Dr. Christine Byrd-Jacobs
Dr. David Linn

Date: Friday, October 7, 2011 8:00 a.m. to 10:00 a.m.
2734 Wood Hall

Abstract:
The purpose of this dissertation is to analyze the neuroprotective effect of an alpha7 nAChR agonist, PNU-282987, and modulator, PNU-120596, in an in vitro model of excitotoxicity and an in vivo model of glaucoma. In culture studies, rat retinas obtained from Long Evans rats were cultured using various concentrations of the PNU compounds to analyze neuroprotection against glutamate-induced excitotoxicity. After three days in culture, retinal ganglion cells (RGCs) were identified using an antibody against Thy 1.1, visualized using a fluorescent dye and quantified. In culture, glutamate significantly decreased the number of RGCs. However, if either PNU compound was introduced before the glutamate insult, complete neuroprotection occurred. In in vivo studies, PNU compounds were injected intravitreally to determine their neuroprotective effect in a rat glaucoma model. Following treatments with PNU compounds, surgery was performed to induce glaucoma by injecting 0.05 ml of 2 mM NaCl into the episcleral veins of right eyes in each rat. The left eye in each rat was left untreated. After one month, rats were euthanized, retinas were removed, flat mounted, fixed and nuclei were stained with cresyl violet or immunostained with an antibody against Thy 1.1. Stained nuclei in the RGC layer in glaucoma-induced retinas were counted and compared to cell counts from untreated retinas. The surgery to induce glaucoma caused a significant loss of cells in the RGC layer within one month after surgery. However, this effect was eliminated if either PNU compound was injected into the right eye an hour before surgery. The results from this study support the hypothesis that the alpha7 agonist, PNU-282987 and modulator, PNU-120596, have a neuroprotective effect in the rat retina. PNU-282987 and PNU-120596 may be viable candidates for future therapeutic pretreatment of glaucoma.