Antioxidant Defense System and Lipid Peroxidation in Patients with Skeletal Fluorosis and in Fluoride-Intoxicated Rabbits

Abstract

Fluorosis is a serious public health problem in many parts of the world where drinking water contains more than 1 ppm of fluoride. The main manifestations of skeletal fluorosis are crippling bone deformities, spinal compressions, and restricted movements of joints. Although fluorosis is irreversible, it could be prevented by appropriate and timely intervention through understanding the process at biochemical and molecular levels. As in the case of many chronic degenerative diseases, increased production of reactive oxygen species (ROS) and lipid peroxidation has been considered to play an important role, even in the pathogenesis of chronic fluoride toxicity. However, there is inconclusive proof for an altered oxidative stress and antioxidant balance in fluorosis, and the existing data are not only conflicting but also contradictory. In the present communication we have evaluated the antioxidant defense system (both enzymatic and nonenzymatic) and lipid peroxidation in both humans from an endemic fluorosis area (5 ppm fluoride in the drinking water) and in rabbits receiving water with 150 ppm of fluoride for six months. There was no significant difference in lipid peroxidation, glutathione, and vitamin C in the blood of human fluorotic patients and fluoride-intoxicated rabbits as compared to respective controls. Neither were there any changes in the activities of catalase, superoxide dismutase, glutathione peroxidase, or glutathione S-transferase in the blood due to fluoride intoxication (of rabbits) or fluorosis in humans. The results together do not subscribe to oxidative stress theory in fluorosis. Thus, in the absence of clear proof of oxidative damage and to counter toxic effects of fluoride through supplementation of antioxidants, extensive investigations are needed to conclusively prove the role of oxidative stress in skeletal fluorosis.

Oxidative stress parameters in rats exposed to fluoride and caffeine

“…30,31 Kirkova et al 26 observed that ASA in low concentrations stimulated the formation of malondialdehyde in liver homogenates but in higher concentrations it inhibited this process. However, Steer et al 13 affirmed that aspirin both in vivo and in vitro protects LDL (low-density lipoproteins) against subsequent oxidative modification, thereby providing an additional mechanism whereby aspirin may protect against atherosclerosis.…”

The levels of trace elements and selected vitamins in goats with chronic fluorosis

“…Thus, if breeding conditions, nutrition, and source of drinking water are identical in both groups, one can assume that the biological effects observed are mainly due to fluoride. Changes of serum mineral substance in fluorosis have been reported in human beings (24) and animals (3,5,6,16,18). Different results depending on animal species, and natural or experimental conditions were reported with concern to mineral level (2,(5)(6)(7)20).…”

“…In addition, vitamin D plays a role in the amelioration of fluoride-induced toxicity (14). Various researchers have also reported a relationship between F and vitamins (9,(15)(16)(17) and between vitamins and the treatment of fluorosis (9)(10)(11). However, studies in this respect in ruminants are very limited (8).…”

Opinion of the Scientific Panel on contaminants in the food chain [CONTAM] related to Fluorine as undesirable substance in animal feed

“…Experimental data indicated that a concentration of 150 mg F -/L in drinking water given over a period of 6 months, induced no gross pathological symptoms, and failed to alter antioxidant enzyme activity (Reddy et al, 2003). In contrast, the application of 10 mg NaF/kg body weight daily for a period of 18 months provokes severe abnormalities of sperm cells, suggesting a role of fluoride in impaired fertility of the male rabbit (Kumar et al, 1994).…”