Long-live euthymic BALB/c-nu mice. I. Survival study suggests body weight as life span predictor

This paper is the first of a series aimed to show the main physiological an d pathological characteristics of male euthymic BALB/c-nu mice, a long-live strain of BALB/c mice bred in our own Institute. In particular, the first two paired papers are respectively devoted to general survival information and disease characteristics. also taking into account very old animals that are of high interest for studies on successful aging. In this paper we rep ort the analysis of survival kinetics, the time course of body weight and t he correlation between body weight and time-at-death. The longitudinal stud y has been performed on 88 male mice. checking individually their body weig ht and date of death and analyzing survival data by a model built by our ow n. Survival analysis shows quite higher longevity (median age: about 29 mon ths) in this population when compared with other BALB/c strains. The most r elevant finding on body weight is its correlation with longevity until the age of 22 months: thinner subjects live longer and lose weight at a lower r ate than their heavier mates. Results have formed the basis on which to pla n the cross-sectional experiment to study pathologies and biological parame ters at different ages. including a group of mice at very advanced ages (34 months). (C) 2001 Elsevier Science Ireland Ltd. All rights reserved..