Radiation-induced life shortening in germfree mice

Abstract

The life span, prevalence of disease and a variety of aging parameters were evaluated in 358 conventional and germfree virgin female mice of the CD-1 line, some of which were exposed to 700 R cobalt-60-γ-radiation at 6 weeks of age. In comparison with the conventional groups, the exposed and nonexposed germfree animals showed a reduction in life span accentuated by irradiation, a reduced prevalence but accelerated appearance-rate of benign and malignant tumors, an increased incidence of amyloidosis and displacement of a series of aging parameters consistent with accelerated aging. These observations are tentatively attributed to the characteristic hyporeactivity of lymphoreticular structures associated with the germfree state and particularly the attendant decrease in the pool of thymic-dependent recirculating small lymphocytes.