The Effects of Radon and its Progeny on Human Skin Cells

Radon-222 is a naturally occurring radioactive gas released from granite rock and uranium-rich soil. High levels are found in Southwest England due to local geology. Radon is known to cause lung cancer, therefore its potential role in skin carcinogenesis is of interest, as Southwest England also has high skin cancer incidence. A novel radium-226 flow-through apparatus was employed to dissolve radon and its progeny into cell media. Cultured human skin fibroblasts (84BR), squamous carcinoma cells (A431) and lung fibroblasts (MRC5) were incubated in this radioactive media +/- total (UVT) or 320 nm cut-on filtered (UVA) ultraviolet radiation (UVR). Cell viability, cytotoxicity, genotoxicity, and mode of cell death was ascertained using neutral red uptake, lactate dehydrogenase, and comet assays, and dual stain flow cytometry respectively. UVR alone induced a cytotoxic dose response more rapidly in skin cells than lung fibroblasts, with both UVT and UVA inducing apoptosis. Increased exposure to UVT/ UVA increased DNA damage with more genotoxicity occurring in MRC5 cells than skin cells. Increasing exposure to radon and its progeny alone produced increased DNA damage within A431 and MRC5 cells (but not 84BR), with considerable cytotoxicity occurring in skin cells at 4 hours via apoptosis. Combining the insults decreased UVR-induced cell death in all cell types with apoptosis occurring more rapidly in skin fibroblasts than neoplastic A431, and greater cell death via apoptosis observed in MRC5 cells. The combined exposures also produced significant genotoxicity, suggesting that radon and its progeny disrupted apoptosis-inducing cellular pathways normally triggered by UVR, allowing genetically damaged cells to survive. Radon levels monitored in some Cornish homes indicated, despite remedial works, many remained above recommended national action levels. Higher levels in winter than summer were also observed. Radon therefore continues to have the potential to contribute to human skin carcinogenesis and thus warrants further study<p></p>

Author dc:creator

• Luke Talbot (21037715)

• radon
• Ultraviolet
• apoptosis
• necrosis
• radiation

Statement dc:rights

• All rights reserved

Identifier

10779/exe.31374118.v1

OAI identifier oai:identifier

oai:figshare.com:article/31374118