In vitro study of the mechanisms of senescence acceleration.

Accelerated senescence can be considered to be an aging process that occurs after development and maturity and is characterized by a higher rate of increase in the degree of senescence than seen in the "normal senescence process." We devised culture methods to determine precise population doublings in cultured fibroblast-like cell lines and subsequently compared the aging process, in vitro, in cell lines established from either accelerated senescence-prone or- resistant strains of mice to obtain evidence of accelerated aging. Fibroblast-like cell lines were established from the dorsal dermis of the newborn accelerated senescence-prone mice of the SAMP11 strain and from accelerated senescence-resistant mice of the SAMR1 strain. All cell lines from both strains showed senescence as evidenced by a crisis in growth; then were immortalized. However, in cell lines from the SAMP11 strain, this growth crisis occurred more rapidly and at earlier population doubling levels than in cell lines from the SAMR1 strain. The methods and materials should aid in the elucidation of mechanisms linked to accelerated senescence in mice.