Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 50, Issue 5 B282-B287, Copyright © 1995 by The Gerontological Society of America
Age-related changes in rat interstitial matrix hydration and serum proteins
BJ Barber, RA Babbitt, S Parameswaran and S Dutta
Center for Biomedical Engineering, University of Kentucky, USA.
Measurements of effects of age-related changes on loose connective tissue
protein concentrations and water are lacking. Tissue hydration is an
important determinant of tissue protein diffusion coefficients and
hydraulic conductivity. Sprague-Dawley rats (ages 11, 30, 57, and 89 wk)
were anesthetized. Blood and mesenteric tissue samples were taken. Tissue
water content was determined by microgravimetric technique. Protein content
was determined by electrophoresis. Tissue hydration decreased 18% between
11 and 89 wk with one-half the fall occurring between 57 and 89 wk. Tissue
albumin concentration decreased 37% between 11 and 89 wk. Serum albumin
increased 22% between 11 and 30 wk and then decreased by 37% to 1.4 g/dl in
89-wk rats. Serum total protein concentration increased by 13% between 11
and 89 wk, whereas tissue total protein concentration decreased 30% with
age to 1.9 g/dl at 89 wk. The results suggest that age-related tissue
dehydration is due, in part, to a shift in the colloid osmotic pressure
components of Starling equilibrium favoring fluid reabsorption.
