Summary of deaths in the control group in toxicity studies in ICR mice

Abstract

We investigated the occurrence of death in ICR mice (Crl: CD1 and Crlj: CD1) up to 31 weeks of age in total 29 of toxicity/carcinogenicity studies between April 2009 and March 2020. Dead/moribund sacrifice occurred in 4 out of 1200 males and 12 out of 1200 females. The presumptive cause of death was hyaline glomerulopathy (1 female), glomerulonephritis (1 male and 1 female), excoriation (1 female), osteosarcoma (1 male), malignant lymphoma (1 male and 3 females), hemorrhage from uterine polyp (1 female), anemia (1 female) and unknown cause (1 male and 4 females).