TEM images of ultrathin sections (×1500). (a,c) Control group, showing the normal histological structure of glomeruli and renal tubules. (b,d) High Cd group, showing capillary endothelial cell proliferation (End), partial basement membrane thickening (BM), renal tubule lumen stenosis, mitochondrial swelling (H) in renal tubular cells, significant vacuolar degeneration (V), and lumen and coagulative necrosis (N).