title: UV radiation increases carcinogenic risks for oral tissues compared to skin.
abstract: People can expose their oral cavities to UV (290-400 nm) by simply opening their mouths while outdoors. They can also have their oral cavities exposed to UV indoors to different UV-emitting devices used for diagnoses, treatments and procedures like teeth whitening. Because the World Health Organization declared UV radiation as a complete human carcinogen in 2009, we asked if oral tissues are at a similar or higher carcinogenic risk compared to skin tissue. To understand the UVB (290-320 nm)-related carcinogenic risks to these tissues, we measured initial DNA damage in the form of cyclobutane pyrimidine dimers (CPD), the repair rate of CPD (24 h) and the number of apoptotic dead cells over time resulting from increasing doses of erythemally weighted UV radiation. We used commercially available 3D-engineered models of human skin (EpiDerm™), gingival (EpiGingival™) and oral (EpiOral™) tissues and developed an analytical approach for our tri-labeling fluorescent procedure to identify total DNA, CPD and apoptotic cells so we can simultaneously quantify DNA repair rates and dead cells. Both DNA repair and apoptotic cell numbers are significantly lower in oral cells compared with skin cells. The combined results suggest UVB-exposed oral tissues are at a significantly higher carcinogenic risk than skin tissues.
authors.affiliation: US Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, MD.
authors.forename: Anant
authors.initials: A
authors.lastname: Agrawal
authors.forename: Eli
authors.initials: E
authors.lastname: Shindell
authors.forename: Fredrick
authors.initials: F
authors.lastname: Jordan
authors.forename: Larissa
authors.initials: L
authors.lastname: Baeva
authors.forename: Joshua
authors.initials: J
authors.lastname: Pfefer
authors.forename: Dianne E
authors.initials: DE
authors.lastname: Godar
mesh_terms: D063646:Carcinogenesis; D004198:Disease Susceptibility; D005455:Fluorescent Antibody Technique; D006801:Humans; D020287:In Situ Nick-End Labeling; D009062:Mouth Neoplasms / Q000209:etiology*; D009381:Neoplasms, Radiation-Induced; D012878:Skin Neoplasms / Q000209:etiology*; D014466:Ultraviolet Rays