Morphological Changes of the Thymus of the Juvenile White Rats Exposed to the Inhalation of Formaldehyde

Abstract

The aim of the article is to study the morphological features of the thymus of the white rats exposed to the inhalation of formaldehyde.Material and methods. 72 white male rats with an initial body weight of 130–150 g were were exposed to formaldehyde at a concentration of 2.766 mg/m3. Exposures were carried out once a day during 60 minutes. Exposure durations were 10, 20, 30, 60 and 90 days. We separately studied the thymus of rats, which, after 60 days of exposure to formaldehyde, were kept for 30 days in standard vivarium conditions (rehabilitation group). The structure of the thymus was studied by light microscopy.Results. The number of cells in an area of 2500 μm2 of the subcapsular zone in animals exposed to formaldehyde for 10, 20, and 30 days was 131.19±4.20, 135.65±7.74, and 135.35±10.83, respectively, which was less than the control set by 4.35%, 4.68% and 3.72%, respectively. After 40 and 60 days, this indicator was below the control by 8.90% and 9.63%.Conclusion. Inhalation of formaldehyde reduces the area of the thymus cortex. Phenomena of inversion of the cortex and the medulla are observed. Under the influence of formaldehyde, a picture of so called «starry sky» is observed in the cortical substance of the thymus. A decrease in the severity of changes in the thymus of rats belonging to the rehabilitation group, in comparison with animals that received 90 exposures, indicates that the changes are reversible.