Correlation of survival time of embryo fibroblasts and their proliferativepotentials with longevity of different mice strains

It is known that the longevity of senescene accelerated mouse (SAM) is sign ificantly reduced. We intended to check the relationship of the SAM shorten ed longevity with some characteristics of their cells in culture. We observ ed the correlation of longevity of SAMP1 (senescence prone strain), SAMR1 ( senescence resistant strain), and CBA mice with proliferative lifespans of their embryo fibroblasts in vitro as well as with the survival time of nond ividing senesced embryo fibroblasts. It was shown that azidothymidine AZT ( 3 muM) increases the survival time of nondividing senesced embryo fibroblas ts. The premature senescence of SAM fibroblasts is associated with accelera ted accumulation of the P-galactosidase-positive cells. Terminal restrictio n fragments of DNA of SAMP1 are more heterogeneous than SAMR1 ones. There i s relatively high telomerase activity tin comparison with CBA mice) in SAM embryos and cell cultures. This activity rapidly decreases during growth in vitro and is restored after spontaneous transformation occurring at a high frequency in both strains. The hypothesis about common mechanisms underlyi ng decreasing of longevity, proliferative potential, and survival time of s enesced nondividing cells is discussed.