Morphological characteristics of laboratory rat's primary and secondary lymphoid organs beyond water‐soluble silicon consumption in repeated studies.

Abstract

Recently we have shown that water‐soluble silicon compounds induced certain morphological changes in different lymphoid organs of laboratory rodents. Here we generalized our results received in timeframe from 2011 until 2014.The primary (thymus) and secondary (spleen, Peyer's patches) lymph organs of 6 weeks old white outbred male rats were investigated. The control animals (group 1; n=10) received standardized drinking water ad libitum, the experimental rats (group 2; n=10) got ad libitum the same water containing sodium metasilicate (10 mg/liter silicon content) during 2 months. First study from 2011 was repeated in 2012 and in 2014. All procedures with rats were performed in accordance with the prevailing guidelines for animals care. The thymus, spleen, Peyer's patches were isolated immediately after decapitation, fixed in 10% formalin, and embedded in paraffin. 5μm thick sections were stained with hematoxylin‐eosin and toluidine blue. Photomicrographs from lymph organs were captured with help of light microscope MIKMED 5 under ×1000 magnification and collected for further morphometric evaluation with SigmaScan Pro 5.0 software. The mean areas of the secondary lymphoid nodules were measured in five fields of view with fixed area per animal per group. Standard error of the mean (SEM) were calculated for all means.The comparative morphometric analysis in 2011 revealed that after two month of treatment the germinative center area of splenic and small intestine's secondary lymph follicles in experimental group were 1,2 times larger (p < 0,05), than in control group.The administration of water‐soluble silicon compounds probably forced the physiological involution of thymus by depletion of lymphocyte amount in thymic cytoreticulum. All these data were confirmed in repeated experiments in 2012 and 2014. Moreover, we received the comparable data from thymic mast cell reaction to the silicon consumption in all serial experiments in 2011, 2012 and 2014: ortochromatic mast cells appeared and metachromatic mast cells underwent to degranulation.In 2011, 2012 and 2014, we also noticed, that 20% of experimental animals, which received water‐soluble silicon compounds, had thymic lymph follicles. Known, that such structures appear in the thymus during autoimmune diseases.Our multi‐annual repeated experiments demonstrated that silicon from drinking water probably can influence humoral immunity processes and this fact cannot exclude the role of water‐soluble silicon compounds in the development of autoimmune diseases.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.