Graduation Year

2021

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Dean's Office

Major Professor

Manas R. Biswal, Ph.D.

Committee Member

Siva Panguluri, Ph.D.

Committee Member

Sarah J. Steinhardt, Pharm D, JD(Esq), M

Keywords

Dextromethorphan, NMDA receptor antagonist, RPE, inflammatory stress, dry-AMD, antioxidants

Abstract

Oxidative stress contributes to the degeneration of retinal pigment epithelial (RPE) cells and photoreceptors that lead to the dry form of age-related macular degeneration. Activation of N-Methyl-D-aspartate (NMDA) receptors contributes to the increase of free radicals that induce oxidative stress-induced changes. Our study investigates if Dextromethorphan, an NMDA receptor antagonist, reverses oxidative stress-induced changes in RPE. We used Paraquat and H2O2 as oxidative stress-inducing agents to induce oxidative damage in human ARPE-19 cells. To illustrate the change in cell viability and measure the apoptosis of ARPE-19 cells from oxidative damage, we performed MTT assay and Annexin V-DAPI flow cytometry analysis. Total RNA and protein from the treated and control samples were analyzed by reverse transcriptase PCR (RT-PCR) to evaluate changes in genes responsible for cell protection and inflammation. The MTT (n=6) and flow cytometry assays (n=3) demonstrated significant cell viability compared to the control cells (p< 0.05) treated H2O2 (400μM) induced oxidative stress. RT-PCR analysis showed induction of protective antioxidant genes (GCLM, GSTM1, NQO1, NRF2, MT1, SOD2) and reduced inflammatory genes (IL1β, IFNy, IL-17, MCP1, TNFα) in response to Dextromethorphan treatment under oxidative stress in ARPE-19 cells. The current findings suggest that dextromethorphan plays a protective role in RPE by mitigating oxidative stress-induced changes.

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