Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
Institute for Animal Experimentation, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan.
PLoS One. 2018 Jul 25;13(7):e0201259. doi: 10.1371/journal.pone.0201259. eCollection 2018.
Surgical site infections (SSIs) represent an important clinical problem associated with increased levels of surgical morbidity and mortality. UVC irradiation during surgery has been considered to represent a possible strategy to prevent the development of SSI. 254-nm UVC induces marked levels of DNA damage by generating cyclobutyl pyrimidine dimers (CPD) in microorganisms. However, this effect is elicited not only in microorganisms, but also in human cells, and chronic exposure to 254-nm UVC has been established to represent a human health hazard. In contrast, despite short wavelength-UVC light, especially 222-nm UVC, having been demonstrated to elicit a bactericidal effect, single irradiation with a high dose of 222-nm UVC energy has been reported to not induce mutagenic or cytotoxic DNA lesions in mammalian cells. However, the effect of chronic irradiation with a high dose of 222-nm UVC to mammalian cells has not been determined. In this study, it was demonstrated that large numbers of CPD-expressing cells were induced in the epidermis of mice following treatment with a small amount of single exposure 254-nm UVC, and then less than half of these cells reduced within 24 h. Chronic 254-nm UVC irradiation was revealed to induce sunburn and desquamation in mouse skin. Histological analysis demonstrated that small numbers of CPD-expressing cells were detected only in hyperkeratotic stratum corneum after chronic irradiation with a high dose of 254-nm UVC, and that significant hyperplasia and intercellular edema were also induced in the epidermis of mice. In contrast, chronic irradiation with 222-nm UVC light was revealed not to induce mutagenic or cytotoxic effects in the epidermis of mice. These results indicated that 222-nm UVC light emitted from the lamp apparatus (or device), which was designed to attenuate harmful light present in wavelengths of more than 230 nm, represents a promising tool for the reduction of SSI incidence in patients and hospital staff.
手术部位感染（SSI）是与手术发病率和死亡率增加相关的重要临床问题。手术期间的 UVC 照射被认为是预防 SSI 发展的一种可能策略。254nm UVC 通过在微生物中产生环丁基嘧啶二聚体（CPD）引起明显的 DNA 损伤水平。然而，这种效应不仅在微生物中被引发，而且在人类细胞中也被引发，并且已经证实慢性暴露于 254nm UVC 对人类健康构成危害。相比之下，尽管已经证明短波长-UVC 光（特别是 222nm UVC）具有杀菌作用，但据报道，单次高剂量 222nm UVC 照射不会在哺乳动物细胞中引起致突变或细胞毒性 DNA 损伤。然而，尚未确定哺乳动物细胞用高剂量 222nm UVC 进行慢性照射的效果。在这项研究中，证明了在小鼠表皮中用少量单次暴露 254nm UVC 处理后，诱导大量表达 CPD 的细胞，并且在 24 小时内这些细胞的数量减少了不到一半。慢性 254nm UVC 照射被揭示会引起小鼠皮肤晒伤和脱皮。组织学分析表明，在慢性高剂量 254nm UVC 照射后，仅在角质过度的角质层中检测到少量表达 CPD 的细胞，并且还会在小鼠表皮中引起显著的过度增生和细胞间水肿。相比之下，慢性 222nm UVC 照射未在小鼠表皮中诱导致突变或细胞毒性作用。这些结果表明，从设计用于衰减波长超过 230nm 的有害光的灯装置（或设备）发出的 222nm UVC 光代表了减少患者和医院工作人员 SSI 发生率的有前途的工具。
