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AN OBSERVATIONAL ASSESSMENT OF AGING IN BROWN NORWAY RATS.
Citation:
MACPHAIL, R. C., P. M. Phillips, D. KURTZ, AND K. JAREMA. AN OBSERVATIONAL ASSESSMENT OF AGING IN BROWN NORWAY RATS. Presented at Society of Toxicology 49th Annual meeting, Salt Lake City, UT, March 07 - 11, 2010.
Impact/Purpose:
An observational assessment was therefore developed that provides rank scores of appearance, posture, mobility, and muscle tone on a 5-point scale.
Description:
The growth of the aging population highlights the need for laboratory animal models that can be used to (1) efficiently monitor the health ofaging research colonies, and (2) aid in unraveling the mechanisms ofsusceptibility to toxic chemicals and disease. An observational assessment was therefore developed that provides rank scores ofappearance, posture, mobility, and muscle tone on a 5-point scale. A score of 1 indicated no impairment while a score of 5 indicated severe impairment. The assessment of a single rat can be completed in about one minute. The assessment was applied to male Brown Norway (BN) rats between the ages of 12 and 36 months (n=32). The results showed that aging-related signs ofimpairment did not appear before 18 months. Assessment scores for each of the measures subsequently increased with age. Variability in scores also increased with age. Comparing these results with the age-related changes in body weight and survival indicated the assessment method was more sensitive and provided unique data on the aging phenotype. Additional studies showed there was no difference in the aging trajectory ofmale Brown Norway rats from two different commercial suppliers. Scores for male BN-F344 hybrid rats (23-27 months) indicated less aging-related impairment than those obtained for BN rats in the same age range. On the other hand, scores for male Long Evans rats at 18 months ofage indicated severe impairment, equivalent to that obtained in 30 month-old BN rats. The observational assessment provides an efficient means to monitor the health ofaging rats and may be a useful tool in studies on aging-related susceptibility to toxicants, drugs and disease. (This abstract does not necessarily reflect USEPA policy.) 2081