Nuclear bodies in rat hepatocytes: Dynamics of appearance and formation during aging and functional loads

Abstract

Using electron microscopy, we studied the morphology of nuclear bodies (NB) in hepatocytes of rat Wistar males of various ages both in intact and upon single bleeding and enterosorption. NB are round formations 2-3 microns in size consisting of loosely packed up chromatin filaments with spherical formations (CFSF) 0.01 micron in size similar to those in prenucleosomal level of chromatin organization. NB are often detected in hepatocytes with the signs of intracellular hyperplasia, granular dystrophy and apoptosis. In intact rats NB are observed only in old rat hepatocytes (in 1-2 per 10 nuclei). Bleeding considerably increases their number and makes NB to appear in young animals. There are 4 stages of NB formation depending on the moment of blood letting: 1--free CFSF in nucleoplasma, 2--CFSF surrounded with a fibrillar zone along the periphery, 3--CFSF and partly condensed chromatin surrounded by a fibrillar zone, 4--completely condensed chromatin surrounded by a fibrillar zone. Enterosorption causes the appearance in old rat hepatocytes of NB at different stages, mainly at stage 4. The nature of NB is not clear, but they obviously reflect the modification in functional activity of relevant genome loci.