Immunolocalization of Na(+)-Dependent Glucose Co-Transporters in Chicken Kidneys in Norm and During T-2 Mycotoxicosis (Primary Study)

Abstract

The kidney plays an essential role in the proper homeostasis of glucose. In the kidney, glucose transport is carried out across cell membranes by two families of glucose transporters-facilitated diffusion glucose transporters (GLUTs) and Na(+)-dependent glucose co-transporters (SGLT family). Among the transporters, sodium-dependent glucose co-transporters play a major role in the kidney's ability to reabsorb glucose. Although the localization of glucose transporters has been extensively studied in mammals, there are still knowledge gaps regarding the localization of SGLTs in birds. The aim of this research was to conduct a comparative study of the immunolocalization of the sodium-dependent glucose co-transporters SGLT1 and SGLT2 in the kidneys of healthy and T-2-mycotoxicated chickens. Immunohistochemical staining was carried out using the polyclonal primary antibodies SGLT1 and SGLT2 (Abcam, UK) in kidney tissue derived from seven healthy and seven T-2-mycotoxicated 7-day-old female layer-type Ross chickens (Gallus gallus domesticus). The sections were stained using an immunohistochemistry kit (Abcam, UK). In the kidneys of the healthy birds, strong staining of SGLT1 and SGLT2 was observed in the cytoplasm of the epithelial cells of the proximal straight and convoluted tubules. In the kidneys of the birds of the T-2 toxin group, weak expression of SGLT1 and SGLT2 with morphological changes occurred, indicating reduced glucose transport in the urinary system during T-2 mycotoxicosis.

Keywords: chicken; immunohistochemistry; mycotoxicosis; sodium-dependent glucose co-transporter.

Figure 1

Na(+)-dependent glucose co-transporter 2 transmembrane transport in bird kidneys. SGLT2 = Na(+)-dependent glucose co-transporter 2; GLUT2 = facilitative glucose transport.

Figure 2

Normal kidney morphology of a 7-day-old chicken: proximal (arrowheads) and distal tubules (arrows) in the cortex of the kidney. Hematoxylin and eosin. Magnification 400×, scale bar 100 µm.

Figure 3

Immunolocalization of the sodium-dependent glucose co-transporter-1 (SGLT1) in kidney tissue (a) in healthy 7-day-old chickens; note the strong expression of SGLT1 in the apical part of the epithelial cells of renal proximal tubules (arrowheads). Magnification 400×, scale bar 50 µm; (b) damaged brush border membranes of proximal tubule’s epithelial cells in intoxicated chicken (arrows). Magnification 400×, scale bar 50 µm.

Figure 4

Immunolocalization of sodium-dependent glucose co-transporter-2 (SGLT2) in (a) strongly stained proximal tubules (arrowheads) of healthy chicken kidney and weakly stained distal tubules (arrows) is observed. Magnification 400×, scale bar 50 µm; (b) the pale staining of proximal renal tubules (arrows) of intoxicated bird group is observed. Magnification 400×, scale bar 50 µm.

Figure 5

SGLT2 in healthy 7-day-old chicken kidneys. Note the unstained collecting ducts (arrows); immunohistochemistry (IHC) magnification 400×, scale bar 50 µm.