Structural and functional changes of mitochondria in myocardial cells from heart failure in plateau

Abstract

MITOCHOKDRIA are the important places for the metabolism of energy in cells, in which sugar, fat and amino acids are eventually required to be oxidized. Energy released through the process of oxidization is stored in the high-energy bond of adenosine triphosphate. It is the effect of oxidate-phosphorylation that provides the main energy for living. In former studies on injury of myocardium that resulted from hypoxia, close attention was paid to the changes of structure and oxidative-phosphorylated function in mitochondria'''. In the present study, our observation on the ultrastructure of myocardium including both human and animal materials under transmission electron microscopy combined with X-ray microanalysis indicated however that cardiac mitochondria play a crucial role in the regulation and accumulation of intracellular calcium during hypoxia and have direct and close relation with the myocardium injury. 1 Materials and methods 1.1 Tissue specimens Eleven cases of human heart specimens were removed from bodies of abrupt heart failure happening soon after entering or coming back from the Tibetan Plateau, which has been excluded by autopsy from other common heart diseases, Keshan disease and primary myocardium diseases. The plateau heart disease is a special kind of heart disease resulting from hypoxia in plateau, which usually led to sudden-death from heart failure (sudden death in plateau) soon after clinic symptoms began to appear no matter how long the course of the disease wasL2]. 1.2 Methods Tissue specimens were removed from the left and right ventricle in sudden-death heart, then processed in a conventional way of the preparations for transmission electron microscopy (TEM), cut into ultra-thin sections and observed under TEM Philips 400T type for ultrastructure, combined with the analysis of elements by energy dispersive spectrum instrument EDAX 9100. The electronic beam was focused on the crystal-like particles to determine the