EFFECT OF LOW DOSES OF RADIATION ON MORPHO-FUNCTIONAL STATE OF SUBMANDIBULAR SALIVARY GLAND IN RATS

Abstract

The paper presents the study of the morpho-functional changes in the submandibular gland under the exposure to low doses of radiation in experiment.
 Material and methods. The experiments were conducted on 80 sexually mature random-bred rats, which were kept in the zone of radiation contamination (zone of permanent radiological control). The external radiation at the moment of the experiment constituted 0.40 and 0.36 mSv due to Cesium-137; internal radiation from separate irradiation sources were 0.16 and 0.11 mSv that are considered to be low doses of radiation. The material for the study (submandibular salivary gland) was taken in terms defined by the experiment from animals euthanized with the overdose of ether anaesthesia. Pieces of the gland were fixed in 10% of the neutral formalin; the sections of the gland were stained with Haematoxylin and Eosin and were studied under the luminous microscope. Microscopic sections were examined for the presence of pathohistological changes in the gland and morphometric investigation of acini and ducts were performed.
 Results and discussion. During 3-6 months, we observed the progressive morphometrically confirmed degenerative changes in the secretory cells of the acini, the reduction of the diameter of the intercalatated and striated ducts in the serous particles of the gland. We also noted the gradual expansion of the ducts of calibers in the mucous particles of the glands, as the epitheliocytes of their wall acquired more mucus. By the end of the 12th months of the study, the area and height of the cells of the serous terminal divisions and the excretory ducts shrinked (due to atrophy). At the same time, the glandular mucous components (acini and ducts) became predominant. Their terminal branches and excreting ducts develop cystic extensions of the lumen. At the same time transport processes such as releasing secretion from the protein and mucous cells of the terminal secretory sections, became impaired.
 Conclusion. Studying the dynamic changes in the tissues of the submandibular gland in rats demonstrated the data about pathohistological changes causing the functional insufficiency of the gland in case of prolonged exposure to low doses of radiation. Quantitative and qualitative insufficiency of the mucus formation and salivation can result in the development of sialolithiasis with its all inherent manifestations. In conditions of the exposure to low-dose ionizing radiation, adaptive mechanisms in the epitheliocytes of the duct walls were noticed to start developing, with their transformation into mucous cells and the formation of stone structures in case of mucus thickening.