Studying Chronic Exposure of Mice to Ultraviolet B Radiation

We're investigating the systemic effects of skin exposure to low dose UVB radiation, specifically at levels below that that cause erythema. Our protocol will allow an understanding of the systemic effects of low dose UVB exposure beyond the direct or local effects on the skin. Our method closely mimics chronic low grade exposure to UVB below erythema levels. Thus we are able to study the endogenous effects of UVB.

[Narrator] To begin, place the anesthetized mouse on a working platform and shave 50 to 60% of its dorsal region. After removing the fur using depilatory cream, place the mouse into a clean, dry recovery cage with cage bedding. Allow the mouse to rest in the home cage with ad libitum food and water. To begin, wear a long sleeved shirt, pants, a lab coat, closed shoes, double gloves, and a face shield to ensure personal safety. Perform the Ultraviolet B irradiation inside a biological hood with the 10 millimeter plexiglass cover lowered and a protective screen in place. Place the Ultraviolet B lamp on the transparent plexiglass chamber. Turn on the Ultraviolet B lamp, and allow it to operate until the intensity stabilizes. Then switch on the Ultraviolet X radiometer, equipped with a Ultraviolet B measuring head to monitor the intensity. Place the cleaned exposure chamber inside the transparent plexiglass chamber with two chambers while the ultraviolet lamp is on or off for the respective ultraviolet or mock exposures. Use a calculator to determine the required time to expose the mouse to the desired Ultraviolet B intensity. Transfer the mouse from the home cage to the exposure chamber for the desired exposure time. Expose the mouse to a Ultraviolet B dose of 50 millijoules per square centimeter, which is a sub-erythematic dose. To validate radiation efficiency, measure the ear and tail pigmentation using a dermal spectrophotometer. Calibrate the spectrophotometer device by setting the baseline with clean plain white paper. Once calibration is complete, position the measurement sensor on the ear or tail of the mouse and record the melanin intensity readings. Gradual and significant increases in melanin levels were observed in both male and female mice exposed to Ultraviolet B radiation over four weeks compared to controls, confirming successful induction of skin pigmentation.