Electron micrographs of sections in the glomeruli of adult male rats in all study groups. a Control group, the glomerulus reveals part of the podocyte cell body (Pd) from which the primary processes (pp) arise. The filtration barrier is formed of many thin foot processes (f), glomerular basement membrane (BM) and fenestrated endothelium (e) of the glomerular capillaries (c). Notice red blood cells (r) in the lumen of the glomerular capillary. b DN group, the filtration barrier appears disturbed; the podocyte foot processes show effacement (F), some areas of the glomerular basement membrane appear thickened (BM) and the glomerular capillary (C) shows disappearance of fenestrated endothelium in some areas (e). Notice the nucleus of the endothelium (Ne). Red blood cells (R) appear in the lumen. c DN + ZnO-NPs group, the filtration barrier is formed of numerous thin foot processes (F) arising from the primary processes (pp) of podocyte, thin glomerular basement membrane (BM) and fenestrated glomerular endothelium (e). The glomerular capillary (C) endothelium has a heterochromatic nucleus (Ne) with red blood cells (R) in the lumen.