A new universal rat restrainer for in vivo exposure to UVR without anesthesia

Purpose: Immobilization of rats is required in many psychological and physiological experiments with rats. The aim was to invent a universal device allowing for adaptation of rats of wide age range and to maximize convenience for in vivo exposure to ultraviolet radiation under un‐anesthetized conditions. Methods: Eighty six‐week‐old Sprague‐Dawley albino female rats were progressively familiarized daily with the restraining device seven days prior to exposure in order to acquire conditioned reflex of place and reduce stress of the awake rodents. In this training period, the animals were handled in the rat restrainer for 5 to 15 minutes during the first day and restrained for 5, 10 and 15 minutes during the second, third and fourth days, respectively. After initial habituation ten minutes preceding the exposure, the animal was fixed in the rat restrainer. Each animal was unilaterally exposed to 8 kJ/m2 UVR‐300nm for 15 minutes without narcosis. After exposure the animal was unfixed and then replaced into the cage. Results: All rats were acclimatized to the limited activities in the rat restrainer during exposure time. The device prevents both intensive head movement and body rotation, making the device effective for in vivo exposure to UVR without anesthesia. Conclusions: The currently designed rat restrainer reduces mobility of rats without need of sedatives, enabling our device to be useful in future projects involving chronic repeated in vivo exposure of the eye to ultraviolet radiation.