Development of a Model for Assessment of Blue Light Activated Toxicity in EpiGingival™ and EpiGingival™-FT Tissues

Traditional phototoxicity models examine activation of test material by ultraviolet A (UVA) light. In these models, the ability of a test chemical to induce toxicity in cells or tissues after light exposure is compared to non-light exposed tissues. While UV-induced toxicity is of great concern, it is clear that lower energy light in the blue spectrum can also activate certain types of chemicals. Blue light is increasingly utilized to activate molecules for a variety of therapeutic uses. Certain types of cancer drugs, topical acne medications and dental whitening chemicals are activated by blue light exposure. MatTek’s human-derived 3D gingival culture EpiGingival™-FT was used to examine the toxicity of several test chemicals after exposure to blue light (475 nm wavelength). Tissues were exposed to negative control (DPBS), Protoporphyrin IX, Blebbistatin and 5-aminolevulinic acid. The tissues were shielded from light or subsequently exposed to light, for approximately 30 minutes at varying mW/cm2. Tissues were then rinsed and allowed to re-cover for 18 to 24 hours at 37°C 5% CO2. Viability of the tissues was examined after recovery using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Light dependent toxicity was observed in the EpiGingival™-FT model after treatment with Protoporphyrin IX and 5-aminolevulinic acid. In addition to examination of the reference chemicals, blue light alone was evaluated for its ability to induce toxicity. Viability of EpiGingival-FT™ tissues was unaffected by increasing blue light doses.

Blue light, EpiGingival FT (GIN-300-FT), elevated temperature, phototoxicity, anti-cancer drugs

protoporphyrin IX, blebbistatin, 5-aminolevulinic acid