Effects of three-month intake of silicon from drinking water on the morphology of avidin-positive mast cells in murine spleen

We studied the inner organ adaptation in experimental rodents to silicon intake from drinking water over many years. Mast cells (MC) are the objects of our special interest. They contain neurotransmitters, biogenic amines and heparin, which can be directly found in them with avidin staining. We studied the reactions of avidin-positive MC in the spleen of laboratory mice, which consumed silicon in their drinking water (20 mg/L) during 3 months. The white laboratory male mice were divided in two groups. The control group of animals received ad libitum bottled drinking water with silicon (10 mg/L), whereas an experimental group received the same water with silicon supplemented with sodium metasilicate nonahydrate, thus achieving total silicon concentration of 20 mg/L. The mass concentration of silicon in water was determined using an inductively coupled plasma emission spectrometer 5110 ICP-OES. Three months later, the animals were sacrificed, the spleen was removed, fixed in 10% neutral formalin and embedded in paraffin. Dewaxed 6-µm sections were incubated for 30 minutes at room temperature and stained with avidin labeled with a green fluorescent label (Avidin, Alexa Fluor^® 488 conjugate, Invitrogen, Germany). The preparations were studied with fluorescence microscope at excitation wavelength of 495 nm. An increased number of avidin-positive MC was observed in the red pulp of spleens from mice treated with drinking water with silicon. The median size of MC in the spleen of mice in the experimental group tended to decrease due to increased proportion of small cells. In mice receiving drinking water with silicon, large mast cells have higher luminescence indices, i.e., they contained more heparin than mast cells from the spleen of animals in control group. Long-term silicon intake with drinking water at a concentration of 20 mg/L for three months leads to the size redistribution of MC population in the red pulp of murine spleen, along with increased fluorescence intensity of large-sized avidin-positive MCs, thus suggesting an increased amount of heparin in these cells.