[Morphologic changes in cardiac muscle in white rats in various models of hypoxia]

The authors have explored the effect of intermittent hypoxia in the cell membrane and histochemical changes in the cardiac muscle cells of the white rat. Every day the animals were exposed to experimental conditions characteristic of 7.000 m of high above sea level (first experimental group) and every odd day (second experimental group). Animals of the experimental groups were sacrificed immediately (first subgroup), 24 hours later (second subgroup) and 7 days after the final exposition (third subgroup). The hypoxical stress elicited the vacuolation of the cardiac muscle fibres of the subendocardiac layer of miocard which persisted, and did not reduce its number, intensity and extensity in the first experimental group, although it reduced its intensity and vacuoles size in the second experimental group, while in fuxinorrhagia which has been presented focally the intensity has been reduced in all the three subgroups of the first experimental group of animals. In preparations of animals from the second group, sacrificed 24 hours after the experiment intensity and extensity fell to the half number of those animals, and completely disappeared in those sacrificed 7 days after the final exposure. Glycogen pools, as well as the activity of sucinat-dehydrogenase were preserved in both experimental groups. It could be concluded that apart from hypoxia model, oxygen deficit, too, elicites ischemical changes in the sense of vacuolation of muscle tissue which does not disappear or its disappearance has been much slower than in positive fuxinorrhagia.(ABSTRACT TRUNCATED AT 250 WORDS)