Histological study of the renal cortical proximal and distal tubules in adult male albino rats following prolonged administration of titanium dioxide nanoparticles and the possible protective role of l-carnosine

Introduction Titanium dioxide (TiO 2) nanoparticles (NPs) are among the most widely used NPs in different industries and in a variety of health products, thus increasing the potential risk of environmental exposure to TiO 2 in the kidney. Aim The aim of this study was to investigate histological changes in renal cortical proximal and distal tubules following prolonged administration of TiO 2 NPs and the possible protective role of l-carnosine. Materials and methods Thirty-five adult male albino rats were distributed randomly among three groups as follows: group I (A, B, and C) (control groups), group II (TiO 2 NPs group), and group III (TiO 2 NPs and l-carnosine). Animals of groups II and III received TiO 2 NPs at a dose of 150 mg/kg body weight and TiO 2 NPs at a dose of 150 mg/kg along with l-carnosine at a dose of 10 mg/kg/day intraperitoneally, respectively, daily for 30 days. At the end of the experiment, all animals were killed under ether anesthesia. Kidneys were dissected and specimens were processed for histological examination using a light microscope after H&E and periodic acid Schiff stains. Other specimens were processed for electron microscopic examination. TiO 2 NPs were characterized by a transmission electron microscope, a Nano Zetasizer particle analyzer, and X-ray diffraction. Results In the control groups, both proximal and distal tubules showed a classical histological structure. In group II, renal tubular cells showed evident changes in the form of cytoplasmic vacuolation, cell lysis, and extrusion of cells into the tubular lumen. Most of the nuclei appeared dark and shrunken. In group III, there was marked histological improvement. Conclusion Prolonged systemic exposure to TiO 2 NPs induced degenerative changes in renal cortical tubules that were evident histologically. Also, it was found that l-carnosine could potentially be a protective agent that can ameliorate the hazardous effect of TiO 2 NPs on the kidney.