Intra- and extracellular reactive oxygen species generated by blue light
Y Omata1, J B Lewis, S Rotenberg
1Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan.
Journal of Biomedical Materials Research. Part A
|February 17, 2006
Summary
Blue light from dental devices generates reactive oxygen species (ROS) both inside and outside cells. These ROS synergize to impact mitochondrial function, with implications for both tissue damage and potential cancer therapy.
Area of Science:
- Cell Biology
- Biochemistry
- Dental Materials Science
Background:
- Blue light from dental curing devices has known biological effects on cells.
- Reactive oxygen species (ROS) are implicated in cellular responses to blue light.
- The specific roles of intracellular versus extracellular ROS in blue light's effects are not fully understood.
Purpose of the Study:
- To test the hypothesis that intracellular and extracellular blue light-generated ROS synergize to depress mitochondrial function.
- To investigate the differential effects of blue light on normal human epidermal keratinocytes (NHEK) and oral squamous cell carcinoma (OSC2) cells.
- To explore the influence of cell culture media on blue light-induced cellular responses.
Main Methods:
- Exposed NHEK and OSC2 cells to blue light (380-500 nm) from a dental photopolymerization source.
- Measured intracellular ROS using the dihydrofluorescein diacetate (DFDA) assay.
- Quantified extracellular ROS using the leucocrystal violet assay and assessed mitochondrial activity via the MTT assay.
Main Results:
- Blue light increased intracellular ROS in both cell types.
- Extracellularly applied ROS rapidly increased intracellular ROS, with greater and longer-lasting effects in NHEK compared to OSC2 cells.
- Cell culture medium composition significantly influenced blue light's suppression of mitochondrial activity, with the greatest suppression in DMEM or NHEK media.
Conclusions:
- Intracellular and extracellular ROS generated by blue light synergize to suppress mitochondrial function in both normal and cancer cells.
- The findings support further investigation into the risks of blue light exposure during dental procedures and its potential therapeutic applications.
- The precise molecular targets mediating these blue light-induced cellular changes remain to be identified.
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