Effects of Fluoride and/or Sulfur Dioxide on Morphology and DNA Integrity in Rats' Hepatic Tissue

This study was aimed to evaluate the toxic effects of fluoride (F) and/or sulfur dioxide (SO₂) on morphology and DNA integrity in liver of male rats. For this, 96 Wistar rats (12-week-old) were randomly divided into four groups after 1-week adaptive breeding: the control group, treated with deionized water; the NaF group, administered high F (100 mg NaF/L in the drinking water); the SO₂ group, with sulfur dioxide in ambient air (15 ppm SO₂, 4 h/day); and NaF + SO₂ group, treated with high F and sulfur dioxide together for 8 consecutive weeks. The body weight, liver organ coefficient, morphology, and DNA damage in the liver of rats were examined. The results showed that the body weight and liver organ coefficient were not significantly changed; however, significant pathological changes of liver tissues were observed in the NaF + SO₂ group compared with the individual treated groups and control group. Furthermore, comet assay indicated that DNA damage in liver was significantly increased in the F and/or SO₂ treatment groups at 2, 4, 6, and 8 weeks, especially at 4 weeks. These results indicate that the liver morphology and DNA integrity of rats are adversely affected by F and/or SO₂ exposure.