Affiliation:
1. Department of Biochemistry, King George’s Medical University, Uttar Pradesh, Lucknow, India
2. Department of Biosciences, Integral University, Lucknow, India
3. Department of Medicine, King George’s Medical University, Uttar Pradesh, Lucknow, India
4. Vice Chancellor, Era University, Lucknow and Former Professor and Head, Department of Biochemistry, King George’s Medical University, Uttar Pradesh, Lucknow, India
Abstract
Abstract
Background:
This study investigates the impact of blue light-emitting diode (LED) lighting on the physiological responses of Wistar rats. The circadian system plays a vital role in regulating physiological functions, allowing organisms to anticipate and adapt to environmental rhythms. The synchronization of endogenous circadian clocks with external cues, such as light-dark cycles, is essential for optimal performance. However, emerging technologies, like blue LED lighting, present new challenges to circadian rhythms, highlighting the need for continued research in this area.
Methods:
The study, approved by the Animal Ethics Committee, involved a total of 12 male Wistar rats, which were divided into two groups: a Control group and a blue light (BL) treated group, each consisting of six rats. The BL model was established by subjecting the rats to 12 h of BL exposure daily for a period of 3 months. Half of the rats were sacrificed at the end of this period, while the remaining rats were transitioned to normal light (NL) conditions for another 3 months before being euthanized. Blood and tissue samples were collected for analysis, including measurements of body weight, blood glucose, insulin, melatonin, lipid profile, as well as messenger RNA expression by reverse transcription-polymerase chain reaction and global DNA methylation by enzyme-linked immunosorbent assay.
Results:
The study found that BL exposure led to a higher monthly increase in body weight, elevated blood glucose levels, and decreased insulin and melatonin levels compared to controls. BL also caused a decrease in total cholesterol, triglycerides, high-density lipoprotein, and low-density lipoprotein. Gene expression analysis revealed downregulation of Period1, Cryptochrome1, and brain and muscle arnt-like protein 1 (Bmal1) in blood and hypothalamus, with significant upregulation upon returning to NL conditions. BL exposure induced hypermethylation in DNA sequences, which partially reverted after returning to NL conditions.
Conclusion:
Our study reveals the broad impact of BL/artificial light contributing to a higher incidence of obesity and metabolic disorders. With the rise of blue-rich LED lighting, more research is needed to understand its long-term effects on health. This study contributes to a deeper understanding of the intricate relationship between BL exposure and metabolic health, emphasizing the importance of informed decisions regarding lighting technologies to mitigate potential health risks.