Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 50, Issue 4 B218-B223, Copyright © 1995 by The Gerontological Society of America
Fibronectin mRNA (FN-V95+) is increased in the liver of old Sprague- Dawley rats: effect of food restriction
H Dorner, B Fischer, G Seefried, D Platt and A Popa-Wagner
Institute of Gerontology, University of Erlangen-Nurnberg, Germany.
Because fibronectin (FN) mRNA has been shown to be increased in the brain
of old rats and during in vivo and in vitro aging of both endothelial cells
and fibroblasts, it was of interest to determine what effect age and
caloric restriction have on the ability of liver cells to express FN mRNA.
The prevalence of fibronectin mRNA containing the alternatively spliced
variant V95 (FN-V95) was examined by RNA gel blot hybridization in the
liver of 10-mo, 18-mo, 30-mo ad lib-fed (AL) and 30-mo food-restricted (FR)
rats. The transcripts coding for FN-V95 mRNA were well expressed in the
liver of 10-mo and 18-mo-old rats. The hybridization signal then increased
(1.3-fold, p < .05) in the liver of 30-mo AL rats vs 10-mo-old rats.
However, the prevalence of FN-V95 mRNA was dramatically decreased
(approximately 4.5-fold, p < .01) in the liver of 30-mo food-restricted
rats as compared to 30-mo-old AL rats. The distribution of FN-V95 mRNA was
also investigated by non- radioactive in situ hybridization (ISH) on liver
frozen sections. The hybridization signal for FN-V95 mRNA was evenly
distributed among liver cells of 10-mo and 18-mo-old rats, while weak
hybridization signals were sparsely scattered on liver sections derived
from 30-mo-old FR rats. In contrast, strong hybridization signals showing a
localized distribution were detected on liver sections obtained from
30-mo-old AL rats. Histologic examination of cryostat sections also
revealed a massive accumulation of lipid droplets in the liver of 30-mo-old
AL rats.(ABSTRACT TRUNCATED AT 250 WORDS)
