Ethanol and age enhances fluoride toxicity through oxidative stress and mitochondrial dysfunctions in rat intestine

Fluoride toxicity and alcohol abuse are the two serious public health problems in many parts of the world. The current study was an attempt to investigate the effect of alcohol administration and age on fluoride toxicity in rat intestine. Six and 18 months old female Sprague Dawley rats were exposed to sodium fluoride (NaF, 25 mg/kg), 30 % ethanol (EtOH, 1 ml/kg), and NaF+EtOH (25 mg/kg+1 ml/kg) for a period of 20, 40, and 90 days. The levels of lipid peroxidation were increased, while the content of reduced glutathione, total, and protein thiol was decreased with NaF treatment. Under these conditions, animals showed an age-related decline in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase which were further aggravated upon NaF or/and EtOH treatment. Mitochondrial respiration rate and the activities of complexes I, II, and IV enzymes of electron transport chain were decreased, while the levels of nitric oxide and citrulline were increased with age and NaF or/and EtOH treatment. Histological examination revealed large reactive lymphoid follicles, excess of lymphocytes in lamina propria of villi, villous edema, focal ileitis, necrosis of villi, and ulceration in NaF- or/and EtOH-treated animals in both the age groups. These findings suggest that fluoride mediate its toxic effects on intestine through oxidative stress and mitochondrial dysfunctions which are further augmented with alcohol consumption and advancing age.