Circadian Variations in Cellular Composition of Lymphoid Organs in Rats with Experimental Endomyometritis

Circadian variations in the cellular composition of the lymphoid organs were studied in female Wistar rats under normal conditions and in experimental endomyometritis. The fractions of CD8⁺ cells (effector killers), CD25⁺ cells (activated/immature lymphocytes), as well as large, medium, small lymphocytes and monocytes/macrophages were assessed at 10.00 and 20.00 h. In the thymus and spleen of rats with endomyometritis, the number of parameters demonstrating significant circadian variations was lower than in intact animals. In the lymph nodes, morning/evening differences appeared for the number of CD8⁺ and CD25⁺ cells and monocytes/macrophages in the para-aortic lymph nodes, the number of large and small lymphocytes and CD8⁺ cells in inguinal lymph nodes, and in the number of large lymphocytes, CD8⁺ cells, and monocytes/macrophages in the ileal lymph nodes. Thus, the development of chronic inflammation in the uterine and vaginal mucosa was accompanied by desynchronosis in the immune system. Hence, circadian rhythms should be taken into consideration in the diagnosis and treatment of the disease.