Ultrastructural Study of Skin Damaged by Accidental Ultraviolet-C Irradiation

Abstract

Ultraviolet-C (UVC) irradiation is commonly used to sterilize vacant sickrooms. Three inpatients and five of their family members were accidentally exposed to UVC irradiation for 30 minutes in a hospital ward in 2003. We examined five of these people 24 hours after the accident. Four persons had no signs or symptoms, but an erythematous patch a rose on the left cheek of a 31-year-old woman, and she developed congestion in her left eye. The skin lesion developed branny scales within two days. Using the same sterilizer, we then studied whether UVC could directly damage cornified cells (keratinized cells without nuclei) of the human epidermis, because UVC is known to be absorbed by DNA in the nucleus and consequently alters the cytoplasm so that cellular damage is exhibited within several days. Scanning electron microscopy revealed that, within 24 hours after irradiation, the surface of the superficial cornified cells became undulated, probably as a result of degeneration of cytoplasmic protein. The regular pattern of keratin filaments of the cornified cells became increasingly irregular after 180 hours. We hypothesized that UVC can produce certain alterations of proteins in the cytoplasm such as keratin in addition to causing DNA damage.