Reversibility of morphological changes in the spleen under the influence of intensive light deprivation

The goal to assess the morphological and functional state of the spleen of white male rats under the influence of light desynchronosis and to analyze the degree of reversibility of these changes. Material and methods. The experiment was carried out in two stages on 60 white male rats, divided into five equal groups: control and four experimental. In the first series of the experiment, the first and second experimental groups were illuminated around the clock for 10 and 21 days. At the second stage, animals of the third and fourth groups were exposed to illumination around the clock for 10 and 21 days, and then kept in natural light for 21 days. The following morphological and morphometric parameters were evaluated: the area of the lymphoid follicle, T- and B-dependent zones of white pulp, the number of reproduction centers and immunoblasts in the T- and B-zones in 10 fields of view. Results. On the 10th day of the experiment, there was an increase in the area of the lymphoid follicle, T- and B-dependent zones, the number of immunoblasts when compared with the control. In animals of the third group, an increase in these indicators was observed. On the 21st day, a decrease in all measured values was noted. In animals of the fourth group, the indicators increased relative to the second experimental one and approached the control values. Conclusion. The detected morphological and functional changes in the spleen are associated with the negative effects of prolonged light deprivation on the organs of the immune system. However, indicators are subject to change.