Choice of rat strain: a comparison of the general pathology and the tumour incidence in 2-year old Sprague-Dawley and Long-Evans rats.
As the choice of species and strain of laboratory animal is of considerable importance in carcinogenicity studies, a two-year, spontaneous carcinogenicity study was performed to compare Sprague-Dawley (Crl: Cobs CD(SD)BR) and Long-Evans rats (CRL: Cobs (LE)BR) under the laboratory conditions at Amboise. Of the 108 animals per strain (54 per sex), no overall differences were noted in survival. Nearly half of the premature deaths in both strains appeared to be due to large pituitary adenomas compressing brain parenchyma. Although the incidence of benign mammary fibroadenomas was similar for both female groups, the incidence of invasive mammary carcinoma was higher in Sprague-Dawley females. Other differences were related to the higher incidence of pancreatic atrophy and nephrosis among Long-Evans rats. Studies of this type can help in the understanding of the pathology of laboratory rodents which may aid in the choice of strain in carcinogenicity studies.
D000818:Animals; D005260:Female; D008297:Male; D009369:Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary*; D051381:Rats; D011919:Rats, Inbred Strains / Q000033:anatomy & histology / Q000502:physiology*; D012376:Rodent Diseases / Q000453:epidemiology* / Q000473:pathology; D012737:Sex Factors; D013045:Species Specificity