[Splenic lymphoid tissue of mice after irradiation with fast carbon ions]

Reorganization of cellular content of splenic functional zones was studied morphometrically in mice after single irradiation with fast carbon ions. It was demonstrated that irradiation does not cause significant changes in microtopography of splenic structures but is accompanied with changes in cytoarchitecture and rearrangement of lymphoid cells throughout the experiment. Two arbitrary stages are determined in lymphoid tissue response. The first one (30 hrs-7 d) is characterized with destructive processes intensification and decrease of small lymphocytes number in all functional zones of the organ. Strong plasmocellular reaction was observed in the organ except for the lymphoid nodules mantle zone in this period as well. On the second stage (15-60 d) orientation of plasmocellular reaction changes along with the tendency of small lymphocytes to restore population (up to 57-79% from the control level on d 60 of the experiment. As a result plasma cell content decreases sharply in all the organ structures. Low level of lymphocytopoiesis was demonstrated in the course of the experiment resulting from cell mitotic activity decline following the irradiation. At the distant period (d 60 following the irradiation) another decrease of cell lymphoid population was noted, which indicates that irradiation with fast carbon ions is suppressive to the animal immune system.