Abstract
BACKGROUND/AIM: This study aimed to evaluate the utility of several biological parameters for the prediction of tumor development and animal welfare in a rat model of urinary bladder cancer. MATERIALS AND METHODS: The control group (n=9) received tap water while the test group (n=12) received the carcinogen N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water. A score sheet with biological variables was used to monitor animals' welfare. Body weight, food and drink consumption and rectal temperature were measured weekly. Blood and urine samples were collected. RESULTS: Animals from the control group exhibited a slightly higher body weight and body weight gain. The final urine volume was higher in BBN group (p<0.05). All animals from the BBN group exhibited macroscopic hematuria at 35th week. Four animals were anemic in the last week of the experiment. CONCLUSION: The routine control of hematuria was a useful non-invasive biomarker of disease progression that may be used as a potential earlier humane endpoint. Animals did not show clinical signs of suffering that justified their sacrifice before the end of the study.