Cellular and Molecular Biomarkers Indicate Precocious in vitro Senescence in Fibroblasts From SAMP6 Mice: Evidence Supporting a Murine Model of Premature Senescence and Osteopenia

A variety of short-lived mouse strains (SAMP strains) and control strains of less abbreviated life span (SAMR strains) have been proposed as murine models of accelerated senescence. Each SAMP strain, in addition to displaying "progeroid" traits of accelerated aging, exhibits a singular age-related pathology. The application of this animal model to the study of normal aging processes has been and remains controversial. Therefore, we have undertaken a study of dermal fibroblasts derived from the short-lived SAMP6 strain, which shows early-onset and progressive osteopenia. We have investigated cellular and molecular characteristics that are associated with in vitro aging of normal human fibroblasts, and which are exacerbated in fibroblasts from patients with Werner syndrome, a human model of premature senescence. We found that SAMP6 dermal fibroblasts, relative to SAMR1 and C57BLJ6 controls, exhibit characteristics of premature or accelerated cellular senescence with regard to in vitro life span, initial growth rate, and patterns of gene expression.