Use of a body condition score technique to assess health status in a rat model of polycystic kidney disease

Simple and noninvasive methods of assessing health and wellbeing are valuable when performing clinical evaluation of rodents used in biomedical research. Body condition score (BCS) techniques have been described for a variety of species, including mice. This method can be a sensitive objective assessment of weight loss in animal models where organ enlargement, ascites, or tumor development may mask weight loss. Although deposition of fat is similar in rats and mice, the mouse BCS technique has not been characterized in rats. Here we used the Han:SPRD rat model for polycystic kidney disease to characterize the effectiveness of the mouse BCS scale when applied to rats. This study showed a positive correlation between BCS score and renal function and a negative correlation between weight and renal function, supporting the use of BCS as an effective, noninvasive method of health assessment in this rat model. Our results also demonstrate that the BCS scale described for mice required a slight modification to capture the delay in fat deposition over the lumbar vertebrae in obese animals.