Accumulation of DNA damage in pre- and posthepatectomized liver of aged rats

Although the majority of the literature supports the concept that an accumulation of DNA damage or a modification in the DNA structure of postmitotic cells occurs with increasing age, there are also several reports that show no DNA changes in these cells with increasing age. In the study reported here, two components of the DNA damage hypothesis of aging were tested. Young (4-6 months) and old (18-20 month) unirradiated or irradiated, pre- and posthepatectomized male Fisher 344 rats were killed, and the posterior lateral lobe of the liver removed. Single cell/nuclei suspensions were made, and the DNA damage accumulated with age or remaining at various times after irradiation was measured using the alkaline elution technique. The results demonstrate that, 1) DNA damage accumulates in rat liver cells with age, and 2) liver cells repair their radiation-induced DNA damage slower in posthepatectomized, but not prehepatectomized aged rats.