OBJECTIVETo evaluate the effects of different oxygen therapy technique (different concentrations of normobaric oxygen and the hyperbaric oxygen) on the ultrastructure of cardiac muscle, lung and liver in rats with acute hydrogen sulfide intoxication.

METHODSOne hundred healthy male Wistar rats were randomly divided into five groups: normal control group (A), poisoned group (B), oxygen therapy group (C), oxygen therapy group (D) and oxygen therapy group (E). After the exposure to 300 ppm H2S for 60 min in a static exposure tank (1 m3), the rats were treated with oxygen therapy, C, D and E groups were given 33% oxygen, 50% oxygen of atmospheric oxygen and hyperbaric oxygen therapy for 100 min, respectively. The rats in normal control group inhaled air under the same environment. After exposure and therapy, the tissues of lung, heart and liver were observed under light microscope and electron microscope.

RESULTSThe results of light microscope examination showed that the broken and not well aligned cardiac myofilaments, cytoplasmic edema and pyknosis could be seen in group B. The well aligned and clear cardiac myofilaments appeared in group C, D and E. The alveolar hemorrhage, edema and inflammatory cells exudation could not be seen in group A. Alveolar epithelial cell edema, unsmooth alveolar edge and alveolar inflammatory cells exudation could be found in group B. The unsmooth alveolar septal borders and pulmonary edema could be seen occasionally in group C and D, the alveolar inflammatory cells exudation could not be seen in group E. The regular hepatic boards and the uniform hepatic cellular nuclei were found in group A. The disordered hepatic boards, widened cellular gaps and cytoplasmic edema could be seen occasionally in group B. The irregular hepatic boards and ballooning degeneration could be seen in group C and D. The regular hepatic boards and uniform cytoplasm could be found in group E. The results of electron microscope examination indicated that the mitochondrial swelling, autolyzing, fuzzy and breakage of myocardial cells were observed in group B; the clear mitochondrial structure appeared in group E. The apoptosis and organelle vacuole of alveolar epithelial cells could be observed in group B. The relatively normal nuclei of alveolar epithelial cells could be seen in group E. The lax cytoplast structure of hepatocytes, unclear nuclear membrane, lumped chromatin, slightly swelled mitochondria and phagosomes were observed in group B. However, no improved change was observed in group C, D and E.

CONCLUSIONHydrogen sulfide could induce the extensive and severe damage of myocardial mitochondria, alveolar epithelial cells and hepatocytes, the oxygen therapy in good time could reduce significantly the myocardial injury, and improve the lung injury to some extent. High-pressure oxygen therapy is better than the normobaric oxygen therapy.