AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 3 389-R394, Copyright © 1992 by American Physiological Society
Dietary lipid modulation of connective tissue matrix in rat abdominal aorta
D. D. Hodgkin, R. D. Gilbert, P. J. Roos, L. B. Sandberg and R. J. Boucek
Division of Perinatal Biology, School of Medicine, Loma Linda University, California 92350.
Dietary lipid modulation of structural and passive mechanical properties of
isolated rat abdominal aortic segments were assessed during the early
developmental period. Rats were raised from conception to 90 days of age on
semisynthetic diets containing various types and amounts of lipids. Aortic
segments from three groups of rats fed high-fat diets (15%, wt/wt)
consisting of olive oil, corn oil, or lard as the sole lipid sources were
compared with those from rats fed a low-fat control diet containing corn
oil (5%, wt/wt). Morphometric analysis of the tunica media demonstrated
that rats raised on diets with a relatively low polyunsaturated fatty acid
content (olive oil and lard) had greater numbers of elastic lamellae than
rats raised on diets with opposite fatty acid indexes (high- and low-fat
corn oil). Changes in elastin content of the tunica media, determined
biochemically, paralleled those seen by morphometric analysis of the
elastic lamellar number. Altered dietary fatty acid ratios were also
associated with changes in smooth muscle cell number. In this regard, a
decreased cellular density was observed in the olive oil and lard diets
compared with the corn oil diet. The olive oil diet was unique amongst the
dietary lipid regimens in raising, whereas the lard-containing diet
lowered, indexes of aortic tissue elasticity. These results demonstrate an
effect of chronic feeding of high dietary fat on the composition and
biomechanical properties of the connective tissue matrix of abdominal
aortic rings from young Sprague-Dawley rats.
