A rat model for the study of growth failure in uremia.

Abstract

Extract: The growth of children with chronic renal disease is poor and the cause of this stunting is not known. Various factors have ben implicated and it is difficult to evaluate their relative importance in clinical studies. Accordingly, there is a need for an animal model, preferably one which enables the effect on growth of a number of factors to be studied separately and over a reasonably short period of time. The growth and food intake of male and female rats rendered uremic by 5/6 nephrectomy was observed between 40 and 70 days of age for male rats and between 35 and 70 days of age for female rats. Final mean body weight for males with uremia (243 g ± 32 g) was significantly less than for control males (323 g ± 24 g); final mean body weights for female rats were also significantly different (172 g ± 17 g; 223 g ± 21 g). The differences in body weight were apparent from 50 days onwards. Final tail length was significantly less in female uremic rats compared with their control subjects (173 mm ± 8 mm; 183 mm ± 7 mm). Uremic rats matched for body weight with control rats consumed significantly fewer calories; for both groups the average difference was about 15%. Multiple regression analysis of weight gain against age and calorie intake suggests that there may be an increase in the calorie cost of growth in rats with uremia, but these findings require confirmation in paired feeding studies. Speculation: These studies suggest that this rat model can be used for the investigation of alterations in energy balance, body composition, and metabolic functions in uremia. It should be possible to study the effects of single variables in the pathogenesis of growth retardation by appropriate manipulations halfway through the growth period.