Journal Article

Species-specific histological characterizations of renal tubules and collecting ducts in the kidneys of cats and dogs

Masaya Hiraishi, Teppei Nakamura, Shunnosuke Kira, Yuki Otani, Osamu Ichii, Takashi Namba, Yasuhiro Kon

2024

Overview

The histomorphological features of normal kidneys in cats and dogs have been revealed despite the high susceptibility of cats to tubulointerstitial damage. Herein, the histological characteristics of the two species were compared. Cytoplasmic lipid droplets (LDs) were abundant in the proximal convoluted tubules (PCTs) of cats aged 23–27 months but scarce in dogs aged 24–27 months. LDs were rarely observed in the distal tubules (DTs) and collecting ducts (CDs) of either species, as visualized by the expression of Tamm–Horsfall protein 1, calbindin-D28K, and aquaporin 2. The occupational area ratio of proximal tubules (PTs) in the renal cortex was higher, but that of DTs or CDs was significantly lower in adult cats than in dogs. Single PT epithelial cells were larger, but PCT, DT, and CD lumens were significantly narrower in adult cats than in dogs. Unlike adults, young cats at 6 months exhibited significantly abundant cytoplasmic LDs in proximal straight tubules, indicating lipid metabolism-related development. Histochemistry of the 21 lectins also revealed variations in glycosylation across different renal tubules and CDs in both species. Sodium-glucose cotransporter 2 was expressed only in PTs, excluding the proximal straight tubules with few LDs in adult cats or the PCTs of young cats and adult dogs. These findings are crucial for understanding species-specific characteristics of renal histomorphology and pathogenesis.

• Publisher: Public Library of Science (PLoS),Public Library of Science
• Subject: Animal euthanasia / Animals / Antibodies / Antigens / Aquaporin 2 / Aquaporins / Biology and Life Sciences / Calbindin-D28K / Cats / Cytoplasm / Distal tubules / Dogs / Ducts / Epithelial cells / Epithelium / Female / Glycosylation / Histochemistry / Histology / Kidney diseases / Kidney Tubules - metabolism / Kidney Tubules - pathology / Kidney Tubules, Collecting - metabolism / Kidney Tubules, Collecting - pathology / Kidneys / Lectins / Lipid Droplets - metabolism / Lipid metabolism / Lipids / Localization / Lumens / Male / Medical research / Medicine and Health Sciences / Pathogenesis / Photonics / Physiological aspects / Proximal tubules / Renal cortex / Renal tubules / Research and Analysis Methods / Research Article / Sodium / Sodium-glucose cotransporter / Species / Species Specificity / Veterinary medicine