2-ethylpyridine, a cigarette smoke component, causes mitochondrial damage in human retinal pigment epithelial cells in vitro

Abstract

Purpose: Our goal was to identify the cellular and molecular effects of 2-ethylpyridine (2-EP, a component of cigarette smoke) on human retinal pigment epithelial cells (ARPE-19) in vitro. Materials and Methods: ARPE-19 cells were exposed to varying concentrations of 2-EP. Cell viability (CV) was measured by a trypan blue dye exclusion assay. Caspase-3/7 and caspase-9 activities were measured by fluorochrome assays. The production of reactive oxygen/nitrogen species (ROS/RNS) was detected with a 2′,7′-dichlorodihydrofluorescein diacetate dye assay. The JC-1 assay was used to measure mitochondrial membrane potential (ΔΨm). Mitochondrial redox potential was measured using a RedoxSensor Red kit and mitochondria were evaluated with Mitotracker dye. Results: After 2-EP exposure, ARPE-19 cells showed significantly decreased CV, increased caspase-3/7 and caspase-9 activities, elevated ROS/RNS levels, decreased ΔΨm value and decreased redox fluorescence when compared with control samples. Conclusions: These results show that 2-EP treatment induced cell death by caspase-dependent apoptosis associated with an oxidative stress and mitochondrial dysfunction. These data represent a possible mechanism by which smoking contributes to age-related macular degeneration and other retinal diseases and identify mitochondria as a target for future therapeutic interventions.

Keywords

• Lasik
• corneal scars
• corneoplastique
• premium cataract surgery
• refractive complications
• radial keratotomy
• pterygium
• pinguecula
• astigmatism
• corneal scars
• Antioxidants
• electromagnetic ration
• glutathione
• lens
• oxidative stress
• 2-ethylpyridine
• apoptosis
• ARPE-19 cells
• cigarette smoke toxicant
• mitochondrial membrane potential
• reactive oxygen/nitrogen species