[Immunohistochemical characteristics of the spleen under the effect of various types of stressors].

The effect of different types of stressors (physical and psychoemotional) on the splenic immunoarchitecture in prepubertal Sprague-Dawley rats was evaluated using the quantitative immunohistochemical methods. Rats aged 1 month were exposed to chronic stress for 5 hours daily during 7 consecutive days. After the last stress session, animals were sacrificed, spleen was obtained for weighing and processed for routine histology and immunohistochemistry (CD3, CD8, CD90, CD20, ED1, PCNA, caspase-3) with subsequent computer image analysis. The results obtained demonstrated that the range of stress-induced immunosuppressive changes in the splenic compartments was associated with the type of stressor. Chronic exposure to purely psychological stress resulted in the decreased volume of the splenic white pulp associated mainly with the reduction of T-cell subcompartments with the decrease in their cellularity and the reduction of volume density of CD90+ and CD8+ cells in them compared to those in age-matched control animals, while the physical stressor affected both T- and B-subcompartments of the white pulp causing the reduction of lymphoid nodule volume, marginal zone width and volume density of CD20+ cells. Hypoplasia of the splenic B-zones was mainly associated with increased splenocyte apoptotic rate while that of the T-zones--with decreased proliferation rate and attenuated traffic of the recent thymic immigrants into the spleen.