Spleen white pulp structural and cellular composition in experimental furosemide-­induced hypomagnesemia

Relevance. Magnesium deficiency in the blood (hypomagnesemia) is due to many reasons, among which loop diuretics (furosemide) occupy a certain place. The role of the spleen in this process has not been determined. The aim of the work was to elucidate the effect of furosemide-­induced hypomagnesemia on the immune structures of the white pulp of rat spleen. Materials and Methods. Furosemide (Lasix® Aventis Pharma Ltd, India) was injected daily intraperitoneally at a dose of 30 mg/kg to the experimental group of white outbred rats for 6 days, animals of the control group received an injection of 0.9% NaCl. Investigated: blood serum for the content of magnesium, calcium, sodium and iron; serial sections of the white pulp of the spleen after staining with hematoxylin and eosin to assess the structure and azure-­II-eosin to assess the cellular composition. With a microscope magnification of 280 times, the ratio (in %) of primary (PLNS) and secondary lymphoid nodules of the spleen (SLNS) was calculated, the following were measured (µm): the diameter of the germinal center (GC), the width of the mantle and marginal zone, the diameter of the periarteriolar lymphoid sheath (PALS). In GC, the peripheral zone of lymphoid nodules, PALS at a magnification of 1500 times per field of view (100 μm2) was counted and presented as a percentage of the number of lymphocytes; macrophages; cells, mitotic and apoptotic elements. Morphometric analysis was carried out using Image ProPlus 6.0 software (Media Cybernetics, USA). Statistical processing was carried out using the Statistica 10.0 software package with the determination of the arithmetic mean (M) and its error (m). Results and Discussion. The administration of furosemide led to a decrease in magnesium in the blood serum by 1.6 times (p < 0.05). In the white pulp of the spleen of animals of the experimental group, the proportion of SLNS decreased by 18.14%, the number of SLNS increased by 42.5% (p < 0.05). The diameter of SLNS increased insignificantly, the diameter of GC and the width of the marginal zone significantly increased by 27.1 and 24.8%, respectively. The proportion of macrophages increased by 20.6% in GC SLNS, and by 17.0% in PALS. The highest increase in the proportion of cells with signs of apoptosis was found in the periarteriolar lymphoid sheath of experimental animals - 34.6% (p < 0.05). Conclusion. Furosemide loading causes the development of dyselementosis, with the most significant loss of magnesium (hypomagnesemia) and has a pronounced effect on the immune parameters of the spleen, represented by white pulp structures. Therefore, correction of the elemental status and monitoring of the state of the spleen in hypomagnesemia caused by the use of loop diuretics is a necessary element in the prevention of complications associated with the use of diuretic drugs.