Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 53, Issue 2 B111-B116, Copyright © 1998 by The Gerontological Society of America
Reduced DNA synthesis in primary cultures of hepatocytes from old mice is restored by thymus grafts
A Basso, L Piantanelli, G Rossolini and GS Roth
Gerontological Research Department, Italian National Research Centers on Aging, Ancona, Italy.
We previously observed in vivo that a neonatal thymus grafted into old mice
can correct age-related changes such as occurrence of hepatocyte tetraploid
nuclei and impaired isoproterenol-induced DNA synthesis in submandibular
glands. The aim of the present paper was to study the influence of age and
thymus on basal and beta-adrenergic-stimulated DNA synthesis using primary
cultures of mouse hepatocytes. In the absence of any adrenergic agents,
cells from young mice show peak DNA synthesis between 36 and 48 h; old mice
show a similar time course, but the peak is significantly reduced
statistically. The main result is represented by the behavior of
hepatocytes from old thymus-grafted mice, which recover the levels of
[3H]-thymidine incorporation toward young-like values. Grafted animals also
show a correction of total DNA content that is increased in old mice. The
addition of isoproterenol does not modify the DNA synthetic pattern,
whereas the antagonist propranolol causes a slight but statistically
significant decrease.
