Different biological effects of exposure to far-UVC (222 nm) and near-UVC (254 nm) irradiation

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Napolea, Renata Spagolla ; Adamoski, Douglas ; Girasole, Alessandra ; Lima, Ellen Nogueira ; Justo-Junior, Amauri da Silva ; Domingues, Romenia ; Silveira, Ana Clara Caznok ; Marques, Rafael Elias ; de Carvalho, Murilo ; Ambrosio, Andre Luis Berteli ; Leme, Adriana Franco Paes ; Dias, Sandra Martha Gomes

• Document type: Journal article
• Source: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY; v. 243, p. 13-pg., 2023-06-01.

Abstract

Ultraviolet C (UVC) light has long been used as a sterilizing agent, primarily through devices that emit at 254 nm. Depending on the dose and duration of exposure, UV 254 nm can cause erythema and photokeratitis and potentially cause skin cancer since it directly modifies nitrogenated nucleic acid bases. Filtered KrCl excimer lamps (emitting mainly at 222 nm) have emerged as safer germicidal tools and have even been proposed as devices to sterilize surgical wounds. All the studies that showed the safety of 222 nm analyzed cell number and viability, erythema generation, epidermal thickening, the formation of genetic lesions such as cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6-4)-pyrimidone photoproducts (6-4PPs) and cancer-inducing potential. Although nucleic acids can absorb and be modified by both UV 254 nm and UV 222 nm equally, compared to UV 254 nm, UV 222 nm is more intensely absorbed by proteins (especially aromatic side chains), causing photooxidation and cross-linking. Here, in addition to analyzing DNA lesion formation, for the first time, we evaluated changes in the proteome and cellular pathways, reactive oxygen species formation, and metalloproteinase (MMP) levels and activity in full-thickness in vitro reconstructed human skin (RHS) exposed to UV 222 nm. We also performed the longest (40 days) in vivo study of UV 222 nm exposure in the HRS/J mouse model at the occupational threshold limit value (TLV) for indirect exposure (25 mJ/cm2) and evaluated overall skin morphology, cellular pathological alterations, CPD and 6-4PP formation and MMP-9 activity. Our study showed that processes related to reactive oxygen species and inflammatory responses were more altered by UV 254 nm than by UV 222 nm. Our chronic in vivo exposure assay using the TLV confirmed that UV 222 nm causes minor damage to the skin. However, alterations in pathways related to skin regeneration raise concerns about direct exposure to UV 222 nm. (AU)

• FAPESP's process: 18/16453-8 - Morphogenetic analysis of the infection mechanisms of the USUV and its effects on neurogenesis in murine model
• Grantee: Murilo de Carvalho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/07600-3 - CIBFar - Center for Innovation in Biodiversity and Drug Discovery
• Grantee: Glaucius Oliva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC