Peculiarities of the Hypoxic State Formation in Rats under Nitrite Methemoglobinemia

In case of experimental methemoglobinemia induced in 80 adult male rats (Wistar) by 5-day injections of
sodium nitrite in a dose of 5 mg / 100 g body weight, was studied the formation of the hypoxic state.
The role of respiratory function, blood circulation, acid-base status of the blood and morphofunctional state of the
heart and lungs tissue in the development of hypoxia in experimental conditions was revealed. It was shown, that the
decreasing of hemoglobin concentration which is capable to oxygenation, was accompanied by a fall of blood oxygen,
the oxygen tension and pH in arterial and mixed venous blood, changes in content and ratio of bicarbonate and buffer
bases. Such changes can be regarded as a development of decompensated metabolic acidosis, however, without the
formation of secondary tissue hypoxia due to the keeping of oxygen delivery by blood and its consumption ratio at
the level > 3. The revealed changes at the tissue level, as well as in the respiratory and circulatory systems, have organ
specific character. In the myocardium, there were signs of mitochondrial dysfunction in the absence of significant cytotoxic
damage of the heart tissue, and in lung tissue a pronounced mitochondrial dysfunction is formed with the development
of severe primary tissue hypoxia. The obtained results should be considered in the developing of advanced
ways of hypoxic damage correction under formation of methemoglobinemia.