Abstract
Purpose:
Cigarette smoking is a major environmental risk factor to age-related macular degeneration. Nicotine is an important chemical component of cigarette. The aim of this study was to investigate the effect of nicotine in the development of age-related retinal degeneration.
Methods:
Adults C57BL/6J mice (6 months old) were divided into four treatment groups: Nicotine (12mg/kg/day); blue light (460 nm, 8h/day); Nicotine + blue light; control (2% saccharine). Retinal lesions were examined at 6 and 12 months after the treatment by fundus imaging, electroretinography (ERG), and Spectral Domain Optical Coherence Tomography (SD-OCT). Eyes were collected at the end of the study for histological and immunological investigations.
Results:
Compared to age-matched control animals, Nicotine alone did no induce retinal degeneration. Blue light treatment resulted in patches of retinal damage in 40% of animals, whereas the combination of blue light and nicotine resulted in retinal damage in 100% of mice. ERG analysis revealed significant reduction in a- and b-waves in light-treated and more in nicotine + light treated mice. Retinal lesions were characterized by patches of RPE death and photoreceptor degeneration accompanied by increased microglial activation and subretinal accumulation in these mice.
Conclusions:
Although nicotine alone is not toxic to the retina, it enhances blue light induced retinal damage during aging. Nicotine is the main chemical component of the E-cigarette. Our results suggest that smoking E-cigarette may not be as safe as we thought. Further study on the effect of nicotine in oxidative stress mediated damage in the aging eye is necessary.