Practical pathology of aging mice

Pettan-Brewer, Christina; Treuting, Piper M.

The mice described herein were obtained from the C57BL/6J (Jackson Laboratories, Bar Harbor, ME) and CB6F1 aged mouse colonies housed at the University of Washington. Additionally, select gross photographs and histopathology examples were obtained from an unrelated inflammatory bowel disease research colony archives (Maggio-Price, University of Washington). In the aging colonies, animals were multiply housed (4Á5 per cage, separate sexes) in ventilated cages containing Bed-O-Cob (Andersons, Maumee, OH) in a specific pathogenfree facility at the University of Washington. Mice were fed irradiated Picolab Rodent Diet 20 #5053 (PMI Nutrition International, Brentwood, MO) and provided reverse osmosis water. All supplies entering animal rooms were autoclaved, and rooms were maintained at 70Á748F, 45Á55% humidity, with 28 air changes per hour and a 12hour light/dark cycle. Sentinel mice were tested quarterly and were negative for endo-and ectoparasites, mouse hepatitis virus, mouse parvovirus, and rotavirus, and they were tested annually for Mycoplasma pulmonis, pneumonia virus of mice, reovirus-3, Sendai virus, and Theiler's murine encephalomyelitis virus. The mice from aging colonies mice were not tested for Helicobacter species or mouse Norovirus. The housing and experimental protocol for the two Helicobacter-infected mice (Fig. 1CÁF ) is described elsewhere (14) . Historical (1980s) dermatitis and alopecia teaching archival cases presented in Fig. 2C ,D lack complete strain and housing history. All animal procedures were approved by the University of Washington Animal Care and Use Committee.