FOLLICULOGENESIS IN THE OVARY OF A RACCOON DOG UNDER CONDITIONS OF RADIATION EXPOSURE
The aim of the study was to determine the morphological changes in the ovaries of raccoon dogs in the age aspect and the dependance on the environment (with different densities of radioactive contamination of the territory and taking into account the removal of anthropogenic load). Scientists have not conducted scientific studies on the morphology of ovaries in raccoon dogs in the exclusion zone (30 km from the Chernobyl nuclear power plant). Therefore, our original studies are relevant for the concept of morphogenesis of the
reproductive apparatus in mammals in the area of removal of anthropogenic load and under the influence of radioactive contamination on the body. As a result of the studies, it was found that in the ovaries of female raccoon dogs living in a less contaminated area with radionuclides, a decrease in the proportion of cortical substance was noted, in which a reduced content of follicles was found, associated with increased death of developing follicles at different stages of their development. In raccoon dogs living in the range with a high content of radionuclides, there is an increase in the proportion of cortical matter and a slight content of atretic follicles (with mild degeneration of the follicular epithelium and thecal cells) in the ovaries, which indicates a lower depletion of the reproductive potential of females in animal populations in the exclusion zone. These morphofunctional changes may be one of the main reasons for the increase in the number of raccoon dogs in the observed area. An age-related study of the histology of the ovaries of raccoon dogs showed that these organs are differentiated into cortical and medulla, where intense folliculogenesis with the presence of atresia is observed. In the area of increased radiation exposure, follicular atresia in the ovaries of raccoon dogs decreases, but in the age aspect it is the other way round: the process intensifies, and resting follicles were more resistant to degenerative changes. The increased elimination of the generative structures of the ovaries can be considered in two ways: both as a result of destructive effects on reproductive function, and, at the same time, as a result of adaptive capabilities of the population (elimination of genetically defective
germ cells aimed at protecting the gene pool of the population).