AGE-ASSOCIATED CHANGES IN CONTENTS OF CONNECTIVE TISSUE MATRIX MACROMOLECULES!!!

[Abbas Bubakar El-ta'alu]

AGE-ASSOCIATED CHANGES IN THE CONTENTS OF COLLAGEN, ELASTIN AND  GLYCOSAMINOGLYCANS IN RATS' SKIN AND AORTA.

El-a'alu A. B*, Kot Y. G**, Falchenko E. V** and Persky Y. E**

V. N. Karazin Kharkov National University. *Department of Human Physiology, **Department of Biochemistry.
Kharkov 61077, Svobody Square  4, Ukraine.
E-mail: abbassido@rambler.ru

ARTICLE IN PRINT

Abstract

           Age-related changes in concentration of the major connective tissue macromolecules - collagen, elastin, separate fractions of glycosaminoglycans - hyaluronic acid, chondroitin-4-sulphate, chondroitin-6- sulphate, heparan sulphate, and dermatan sulphate, as well as their proportion in both the skin and aorta were studied. The aim of this work was to investigate these age-related changes.
           It was shown that, age-related increases in collagen content in both the skin and aorta take place, and at  the same time, a decrease in that of elastin in these tissues, was observed. The contents of hyaluronic acid, chondroitin sulphates, heparan sulphate and dermatan sulphate in the skin increase with age. Contrarily, in the aorta, a decrease in concentrations of hyaluronic acid and dermatan sulphate takes place as an individual ages, while those of chondroitin sulphates and heparan sulphate, increase.

Keywords: Connective tissue, collagen, elastin, glycosaminoglycans.

Introduction

           It has been shown that, distinct age-related changes, in most part of ontogenesis, take place in the concentrations of collagen, elastin, and glycosaminoglycans. These phenomena  must lead to changes in the structural and functional properties of  tissues.
           Elasticity of the skin and aorta decrease with age, while their hardness or regitity increases. This is specially important when considering mechanisms of development of age-related pathologies of the cardiovascular system, as for example, a change in the qualitative and quantitative composition of the wall of vessels, which occupies an important place in the mechanism of age-related development of sclerosis. Howerver, it is not only changes in the contents of collagen and elastin that determine the structure and respective functional properties of the connective tissue. These properties, are as well determined by polysaccharides – glycosaminoglycans, one part of which are structural components of proteoglycans, and the other, that of the amorphous "ground substance". Side chains of proteoglycans, made up of glycosaminoglycans, are interwoven with collagen fibres, and create a dense three-dimentional network, which provides a selective passage to different macromolecules through it, as well as strong spatial structure (Al Jamal, 2001; Yanagishita, 1993). Generally accepted, is the connection between age, atherosclerosis and changes in concentration ratios of hyaluronic acid/chondroitin sulphates. However, there are few data that complexly reflect age-associated changes in the contents of collagen, elastin and main glycosaminoglycans of the skin and aorta.