[Intranuclear inclusions in the cells of different tissues of the aging rat].

Ultrastructure of neuronal and glial nuclei has been studied in various parts of the CNS, in parenchymatous cells of internal organs, in endotheliocytes and pericytes of their blood capillaries in intact rats--mature (6-8-month-old) and old (26-28-month-old), as well as at certain experimental influences. In all the cellular populations studied (most often in neurons), various in their structure, intranuclear inclusions (INI) have been revealed, that are considered as five main types. The number of INI increases sharply at ageing, that is especially noticeable under experimental conditions. Some INI are situated in morphologically preserved, actively working cells, being normal components of the nucleus, others--reflect profound rearrangements of nuclear proteins, disturbances in lipid metabolism up to irreversible destructive processes in the nucleus.