Systemic effects of H₂S inhalation at human equivalent dose of pathologic halitosis on rats

Halitosis is composed by hundreds of toxic gases. It is still not clear whether halitosis gases self-inhaled by halitosis patients cause side effects. The aim of the study was to investigate the effect of H₂S inhalation at a low concentration (human equivalent dose of pathologic halitosis) on rats.

The threshold level of pathologic halitosis perceived by humans at 250 ppb of H₂S was converted to rat equivalent concentration (4.15 ppm). In the experimental group, 8 rats were exposed to H₂S via continuous inhalation but not the control rats. After 50 days, blood parameters were measured and tissue samples were obtained from the brain, kidney and liver and examined histopathologically to determine any systemic effect.

While aspartate transaminase, creatine kinase-MB and lactate dehydrogenase levels were found to be significantly elevated, carbondioxide and alkaline phosphatase were decreased in experimental rats. Other blood parameters were not changed significantly. Experimental rats lost weight and became anxious. Histopathological examination showed mononuclear inflammatory cell invasion in the portal areas, nuclear glycogen vacuoles in the parenchymal area, single-cell necrosis in a few foci, clear expansion in the central hepatic vein and sinusoids, hyperplasia in Kupffer cells and potential fibrous tissue expansion in the portal areas in the experimental rats. However, no considerable histologic damage was observed in the brain and kidney specimens.

It can be concluded that H₂S inhalation equivalent to pathologic halitosis producing level in humans may lead to systemic effects, particularly heart or liver damage in rats.