Age related changes in perimicrovascular protein distribution.
Barber, B. J., S. Dutta, S. Parameswaran, and R. A. Babbitt.
Center for Biomedical Engineering, University of Kentucky,
Lexington, Kentucky
APStracts 2:0198H, 1995.
The diffusion hypothesis for physiological aging proposes that an
increase in interstitial matrix fiber to gel ratio causes a decrease
in nutrient diffusion to the cells. This hypothesis predicts a
decrease in interstitial matrix protein with age. The objective was
to test this hypothesis by determining age related changes in plasma
protein distribution in perimicrovascular and distal regions of rat
mesentery interstitial matrix. Rats, 77, 140, 210, 315, 455 and 630
days old, were anesthetized with sodium pentobarbital and a
mesenteric loop was exteriorized. Intravital video
microspectrophotometry was performed using wavelengths of 280, 320,
and 700 nm. Perimicrovascular protein concentrations from the protein
absorbance images were used to obtain the histogram, mean and
skewness of the proximal and distal protein concentration
distribution. An exponential gradient model was also used to obtain
the proximal and distal protein concentration and gradient decay
constants. Proximal protein concentration increased from 77 to 140
day old rat and then decreased gradually through 210, 315, 455 and
630 day old rats. Distal concentration decreased gradually from 140
to 630 day old rats. There was an increase in positive skewness of
the proximal protein distributions from 140 through 630 day rats. We
found an age-related decrease in perimicrovascular protein and
propose that this is due to a decrease in protein permeability with
age. The results support the diffusion theory of aging.
Received 28 March 1994; accepted in final form 28 April 1995.
APS Manuscript Number H277-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.