Impact of Chronic Sodium Fluoride Toxicity on Antioxidant Capacity, Biochemical Parameters, and Histomorphology in Cardiac, Hepatic, and Renal Tissues of Wistar Rats

The study was designed to determine the fluoride distribution after its oral exposure in drinking water and its associated impact on biochemical, antioxidant markers and histology in the liver, kidney, and heart of male Wistar rats. On 100 ppm exposure, the highest accretion of fluoride occurred in the liver followed by the kidney and heart. Fluoride exposure significantly (p˂0.05) increased the plasma levels of dehydrogenase, aminotransferases, kidney injury molecule-1 (KIM-1), and other plasma renal biomarkers but decreased the levels of total plasma proteins and albumin in a dose-dependent manner. Reduction (p˂0.05) in the activities of antioxidant enzymes viz. acetylcholinesterase, arylesterase, superoxide dismutase, catalase, glutathione peroxidase, and reductase with increased levels of protein and lipid peroxidation was recorded in the liver, kidney, and heart of fluoride-administered rats. Fluoride exposure (100 ppm) induced lipid peroxidation was highest in kidney (4.4 times) followed by liver (2.6 times) and heart (2.5 times) and as compared to their respective control. The percent rise in protein oxidation at 30% was almost equal in the kidney and liver but was 21.5% in the heart as compared to control. The histopathological alterations observed included congestion and hemorrhage along with degeneration and necrosis of parenchymal cells in hepato-renal tissues and myocardium, severity of which varied in a dose-dependent manner. Taken together, fluoride distribution in the liver, heart, and kidney after chronic fluoride intake correlated well with fluoride-induced hepatic and cardio-renal toxicity in a concentration-dependent manner. These results draw attention that chronic fluoride intake pose a significant health risk for human and animal residents of fluoride endemic areas.