ISSN 2415-3060 (print), ISSN 2522-4972 (online)
  • 13 of 67
JMBS 2020, 5(4): 110–116
Experimental Medicine and Morphology

The Effect of Low Doses of Ionizing Radiation on Odontogenesis in Fetal Rats

Cheshko N. N.

The purpose of the study was to establish the effect of low doses of ionizing radiation on the structure of tooth germs in ontogenesis and to identify the nature of possible changes. Material and methods. The experiments were carried out on albino rats mongrel gregarious breeding. Gravid female rats were exposed to chronic irradiation on «Gammarid 192/120 unit» at 110 mR/h power of exposition for 16 days at the Institute of Radiobiology of the National Academy of Sciences of the Republic of Belarus. The total dose absorbed by the fetuses was 0.38 Gy. Another group of gravid female rats (control) was housed in standard vivarium conditions. The controls were not irradiated. Gravid female rats were sacrificed by decapitation under chloroform anesthesia. Rats’ fetuses were extirpated from the uterus and were decapitated. The material was fixed in 10% neutral formalin and embedded in paraffin by standard methodology. Sagittal «serial-selective» sections were stained with hematoxylin and eosin, picrofuchsin after van Gieson sum content of DNA and RNA, which was evaluated by 5-mark scale, revealed by the method of Einarson, elastic fibers (Hart), argyrophil ones (Bilshovsky in G. Berlov's modification). Proliferative activity was determined according to the method of I. A. Kazantseva. The number of cellular layers was also counted. Using the image analysis system "Bioscan-AT", the area and thickness of the structures of tooth germs were determined by contour measurements. Results and discussion. Low doses of ionizing radiation did not interfere with the genetically determined odontogenesis process in 16-day-old fetal rats, but they significantly reduced the proliferative activity of the cells. Chronic irradiation caused 3 times decrease in the mitotic activity of tooth germs in 16-day-old fetal rats. This, in turn, resulted in the decrease in the size, number of cell layers, shape change, delay and impairment of tooth germ differentiation, lack of “concentric structures”, their description hasn’t been found in the literature. Conclusion. Thus, small doses of ionizing radiation did not violate the genetically programmed course of odontogenesis, but caused a number of changes that can play a negative role in the further stages of dental development and in the postnatal period.

Keywords: odontogenesis, ionizing radiation, low doses, rat

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