Aravitskyi Y. Structure and morphogenesis of thymus in the postnatal period after prenatal introduction of staphylococcal anatoxin and dexamethasone. (anatomical experimental research)

The thesis is devoted to the clarification of the peculiarities of the thymus structure and morphogenesis in the postnatal period after intrauterine introduction of staphylococcal anatoxin and dexamethasone with by means of morphometric, histological, lectinhistochemical, immunohistochemical and statistical methods. It was supplemented that after prenatal administration of dexamethasone, a decrease of cortico-medullary ratio by 36% on the 1st day of life was observed, if to compare with the intact animals, mainly due to a decrease in the relative area of the inner cortex (by 44.9%), and up to 30th day this index hadn't reached the reference values. It's been proved that after prenatal introduction of staphylococcal toxoid there was a more intensive accumulation of the benzidine label to the lentil lectin from the 3rd to the 9th day, and the amount of LCA+-dendritic cells is bigger during the first 3 days with a max increase by 58.8% on the 2nd day in comparison with reference indexes. In addition, there was an increase in the number of WGA+-epithelial cells in the thymic cortex and medulla during the first 3 days and on the 30th day of postnatal life, accompanied by more intensive expression of receptors to N-acetyl-D-glucosamine during first 9 days of the postnatal period in cortex (+++) and during 3–5 days of life in the medulla (+++), compared with expression level (++) in intact animals. It was established that administration of dexamethasone to rats in the antenatal period leads to a decrease in the intensity of expression of cytokeratins 5/14 receptors during the first 2 weeks of life and to a progressive decrease in the area occupied by CK 5/14+-epitheliocytes throughout the observation period (on the 1st day relative area of CK 5/14+-cells is by 33.1% less, and by the 30th day it is by 63.5% less) compared to the intact group of animals. It was found that in the group of antigen-primed animals there was an increase in the expression of cytokeratins 5/14 receptors during the all period of observation with a maximum in the first 3 days, and the specific area occupied by CK 5/14+-epitheliocytes was bigger during first 9 days after birth (particularly by 59.1% on the 1st day), if to compare with intact group of animals.