Distribution of Fluoride in Plasma, Brain, and Bones and Associated Oxidative Damage After Induced Chronic Fluorosis in Wistar Rats.

The study was aimed to determine fluoride levels in plasma, brain, and bones of Wistar rats following chronic administration of fluoride at different dose levels and the consequent oxidative damage inflicted in these tissues. Brain histomorphology and bone radiographs were also evaluated to assess the extent of damage in these organs. Eighteen rats were randomly divided into three groups with six animals in each group. Group I served as control and groups II and III received 50 and 100 ppm fluoride in tap water, respectively for 180 days. A dose-dependent rise in the levels of fluoride in plasma, brain, and bones was observed in rats. Significant (P < 0.05) alterations in levels of total thiols, glutathione peroxidase, glutathione reductase, acetylcholinesterase, catalase, superoxide dismutase, lipids, as well as protein peroxidation in blood and brain were observed as compared to control in a dose-dependent manner. Radiological examination of bone revealed thinning of bone cortex with haphazard ossification, reduced bone density, and widening of marrow cavity indicating occurrence of flawed bone remodeling upon chronic fluoride exposure. Improper mineralization in bones of intoxicated rats indirectly reflected reduced bone tensile strength. Moreover, alterations in plasma Ca:P ratio and high levels of fluoride in bone ash indicated that chronic fluoride exposure leads to alterations in the bone matrix further corroborating the radio-graphical findings. Additionally, severe microscopic alterations were recorded in the cerebrum and cerebellum of treated rats which included neuronal necrosis, gliosis, spongiosis, perivascular cuffing, congestion, and hemorrhage which correlated well with oxidative changes induced by fluoride intoxication in the brain tissue of rats.