Effect of Chronic Fluorosis on Lipid Peroxidation and Histology of Kidney Tissues in First- and Second-Generation Rats

Abstract

This experiment was designed to investigate the lipid peroxidation and histological effects of chronic fluorosis on first- and second-generation rat kidney tissues. Sixteen virgin female Wistar rats were mated with eight males (2: 1) for approx 12 h to obtain first-generation rats. Mating was confirmed by the presence of sperm in vaginal smears. Sperm in vaginal smears was observed in 10 of 16 rats (d 0). These rats were identified as pregnant and included in this experiment. Pregnant rats were divided into two experimental groups (control and fluoride-supplemented), each containing five rats. The pregnant rats in the fluoride-supplemented group were exposed to 30 mg/L sodium fluoride (NaF) in commercial drinking water containing 0.07 mg/L NaF throughout the gestation and the lactation periods. After the lactation period, young animals (first generation [F1]) were exposed to the same amount of NaF in drinking water for 4 mo. At the end of the 4-mo experimental period, nine randomly chosen male rats (F1) were sacrificed, and the kidneys were removed for the histological and lipid peroxidation examinations. The remaining eight female rats were mated with four males (2: 1) for approx 12 h to obtain second-generation rats. Six female were identified as pregnant, and treated similarly throughout the gestation and the lactation periods. After the lactation period, the young male rats (second-generation male rats [F2]) were also treated similarly for 4 mo. At the end of the 4-mo experimental period, nine randomly chosen male rats (F2) were sacrificed, and the kidneys were removed for the histological and lipid peroxidation examinations. The rats in the control groups underwent the same procedure without NaF supplementation. It was found that the plasma fluoride and kidney TBARS levels of fluoride-supplemented F1 and F2 rats were higher than controls. Hydropic epithelial cell degenerations and moderate tubular dilatation were observed in some proximal and distal tubules. There were markedly focal mononuclear cell infiltrations and hemorrhage at some areas of the interstitium, especially at the corticomedullar junction. Mononuclear cell infiltrations were also evident in some peritubular and perivascular areas. Most of the vascular structures were congestive. Many Bowman capsules were narrowed. The severe degenerative changes in most of the shrunken glomerules and vascular congestion were also observed.

Molecular Mechanisms of Cytotoxicity and Apoptosis Induced by Inorganic Fluoride

“…Wistar rats, exposed to high fluoride doses, also showed enhanced LPO in their RBCs [108][109][110][111], liver [108,110,111], and brain [108,110]. Karaoz et al [112] showed that exposure of the pregnant rats and their offsprings during first month of life to fluoride leads to kidney tissue changes and LPO in the first and second generation of rats. A direct link between fluoride-induced apoptosis and elevated LPO was shown in the pig [30] and rat [31] hepatocytes.…”

Taurine Ameliorates Renal Oxidative Damage and Thyroid Dysfunction in Rats Chronically Exposed to Fluoride

“…Moreover, thyroid gland has been reported to have a strong capacity for absorbing and accumulating fluoride [11]. Indeed, previous laboratory investigations have demonstrated that excessive exposure to fluoride caused histopathological damage and altered the functional responses of the kidney and thyroid gland [12,13]. Moreover, endemic fluorosis is a global concern because several millions of people are affected.…”

Fluoride Toxicity and Status of Serum Thyroid Hormones, Brain Histopathology, and Learning Memory in Rats: A Multigenerational Assessment

“…The study of more than one generation allows detection not only of any effects on adult reproduction but also of effects on subsequent generations due to exposure in utero and early postnatally. The latest evaluation of sodium fluoride administration through multiple generations has been made previously in general aspects by Collins et al [18,19], in the myocardium, lung, kidney, and testis by Cicek et al [20], Aydin et al [21], Karaoz et al [22], and Meral et al [23] respectively, but brain tissue has not been studied specifically in multigeneration animals. Due to the lack of information on multigeneration studies concerning fluoride-induced changes on the thyroid hormone status, the histopathology of discrete brain regions, and the resultant alterations in acetylcholine esterase levels and the learning and memory abilities, the present study was undertaken.…”