DNA Repair Activity in the Skin of Day and Night Shift Workers

• Ultraviolet B Radiation (Radiation): One skin punch biopsy will be taken to the laboratory for exposure to ultraviolet B radiation. After 1-hour incubation, the biopsies will be bisected in half.
• No Ultraviolet B Radiation (Other): One skin punch biopsy will be taken to the laboratory and will be kept as a non-irradiated control.

Primary outcomes

• Expression level of the DNA repair factor XPA at two times of the day in the skin of day and night shift workers. [After 1 hour incubation from ultraviolet B radiation exposure.]: Reverse transcription quantitative PCR (RT-qPCR) and immunohistochemistry will be used to measure XPA expression at the mRNA and protein level, respectively, in skin samples obtained at 8 am and 4 pm.
• Expression levels of core clock genes at two times of the day in the skin of day and night shift works. [After 1 hour incubation from ultraviolet B radiation exposure.]: Reverse Transcription Quantitative PCR (RT-qPCR) is used to measure the core circadian clock gene expression at the mRNA level in the skin samples obtained at 8 AM and 4 PM.
• Activity of the nucleotide excision repair (NER) system at two times of the day in day and night shift workers. [After 1 hour incubation from ultraviolet B radiation exposure.]: A biochemical assay of nucleotide excision repair is used to measure NER in the skin samples obtained at 8 AM and 4 PM.
• Activation of DNA damage kinase signaling pathways at two times of the day in the skin of day and night shift workers. [After 1 hour incubation from ultraviolet B radiation exposure.]: Immunohistochemistry is used to measure DNA damage kinase signaling (phosphorylated Chk1 and p53) in the skin samples obtained at 8 AM and 4 PM.

Sex: All, ages: 18 Years to 40 Years, accepts healthy volunteers

Inclusion Criteria:

* Male/Female
* Fair skin (Fitzpatrick types I and II)
* Age 18 to 40
* Able to comprehend procedures/risks
* Primarily work and are awake during normal daylight hours (6 am to 6 pm), or primarily work and are awake during night shifts hours (between the hours of 6 pm and 6 am) or may work a mixture of these shifts over the past 3 months. Rotating shifts will be categorized based on the majority of hours worked on average during the last 3 months. Able to fill out a 3-month calendar of work schedule.

Exclusion Criteria:

* Known photosensitivity
* Currently on photosensitizing medications
* Diabetes Mellitus
* On any hormonal agents (e.g., birth control pills)
* History of abnormal scarring
* History of skin infections
* History of skin cancers
* History of sleep disorders such as sleep apnea or insomnia
* Known allergy to lidocaine local anesthetic
* Pregnancy or nursing
* Other serious health issues

• Informed Consent Form (PDF, 2022-05-02)

• Jeffrey B Travers, MD, PhD, Principal investigator, Wright State University