MORPHOLOGIC CHANGES IN MESENTERIC LYMPH NODES OF MICE IN THE PERIOD OF REHABILITATION AFTER COMPLETION OF PROLONGED COMBINED RADIATION AND CHEMICAL EXPOSURE
Structural properties of mesenteric lymph nodes from male mice F1 (CBA x C57/BL6, initial age 30-35 days and mass 20-23 g) were examined in different periods of 63-d radiation exposure and 90-d post-exposure. Animals were exposed to γ-radiation on <sup>137</sup>Cs source GОBO-60. Dose rate amounted to 25 cGy/h. Mice received 350 cGHy total from fractionated irradiation by 50 cGy per a week over 10 weeks. During subsequent 70 days the mice were subjected to chemical effects of acetone, acetaldehyde and ethanol vapors according to the experimental procedure adopted at IBMP. Purpose was to examine morphology of mesenteric lymph nodes over the period of 3-m mice recovery from the prolonged combined radiation and chemical exposure. Longitudinal histologic sections of 5-7 µm in thickness were stained by hematoxyin-esosin according to Van Gieson. On exposure completion it was found that size of mesenteric lymph nodes was decreased and so were length, width and areas of lymphoid nodes; capsules and trabecules of lymph nodes grew in thickness, lymph sinuses expanded and Billroth's strands narrowed. Cell composition of the lymphoid tissue recovered only by day 90, when percentages of lymphocytes, lymphoblasts, macrophagocytes, plasmocytes and degenerating cells were similar to controls.