A groundbreaking study has uncovered that micro and nano plastics can impair the antioxidant functions of retinal cells and accelerate cellular aging. Researchers found that activating the stress-regulating protein SIRT1 mitigated this damaging response, potentially opening new avenues for retinal protection research.
Korea University Guro Hospital announced on Monday that a research team led by Professor Song Jong-seok analyzed the effects of micro and nano plastics on human retinal pigment epithelial cells and rat retinas.
The study was a collaborative effort involving Professor Kim Woo-jin from Korea University Guro Hospital, Professor Kim Dong-hyun from Korea University Anam Hospital, and researchers Kang Ri, Park Jun-bong, and Kim Ok-kyo from Korea University College of Medicine.
Retinal pigment epithelial cells, located outside the light-sensitive photoreceptor cells, play a crucial role in providing nutrients and removing waste. Damage to these cells can significantly impact retinal function and vision maintenance.
The research team exposed human retinal pigment epithelial cells to micro plastics (approximately 2 micrometers in diameter) and nano plastics (50 nanometers in diameter) at varying concentrations and durations. They then measured cell viability, reactive oxygen species (ROS) production, antioxidant enzyme levels, SIRT1 expression, and the degree of cellular aging.
The team also injected plastic particles into the vitreous of rat eyes and observed changes in retinal tissue after seven days.
To put the size into perspective, one micrometer is one-thousandth of a millimeter, while one nanometer is one-millionth of a millimeter. The 50-nanometer nano plastics used in this experiment are about 40 times smaller in diameter than the 2-micrometer micro plastics.
Results showed that higher concentrations of micro and nano plastics and longer exposure times led to a decrease in viable retinal cells. While oxidative stress and aged cells increased, levels of SIRT1 (which helps cells respond to stress) and antioxidant enzymes SOD1, SOD2, and CAT decreased.
Interestingly, in cell experiments, the smaller nano plastics caused more ROS production and cellular aging than the larger micro plastics.
The research team then administered SRT1720, a compound known to activate SIRT1. This treatment resulted in reduced ROS and cellular aging, and the previously diminished antioxidant enzymes recovered. These protective effects were confirmed in both human retinal cells and rat retinal tissue.
Based on these findings, the team concluded that micro and nano plastics could impair SIRT1 and antioxidant functions, leading to retinal cell damage. However, activating SIRT1 could potentially alleviate this response.
It’s important to note that this study represents preclinical research where plastic particles were directly exposed to cultured human retinal cells and rat eyes. Further investigation is needed to determine whether everyday exposure to micro and nano plastics causes similar damage to human retinas and if SIRT1-activating compounds can be safely used in clinical treatments.
Professor Song stated that the research confirms that micro and nano plastics can reduce the stress response and antioxidant function of retinal cells, promoting cellular aging. The fact that activating SIRT1 reduced the damaging response suggests a promising avenue for developing treatments to prevent or mitigate retinal damage caused by environmental pollutants.
He emphasized the need for further studies to closely examine the effects of long-term and repeated exposure to micro and nano plastics on retinal and visual functions. Additionally, follow-up research will focus on translating SIRT1-based retinal protection strategies into viable clinical treatments.
The groundbreaking findings of this study were published in the prestigious international environmental journal Environmental Pollution under the title “Protective Effects of SIRT1 Activation Against Retinal Damage Induced by Polystyrene Micro and Nano Plastics Exposure.”
