Comet Assay of DNA Damage in Brain Cells of Offspring Rats Exposed to Long-term Intake High Fluoride and Low Iodine

摘要

To assess damage to DNA in their brain cells of offspring rats exposed to high fluoride and/or low iodine, 32 Wistar rats were divided randomly into four groups of eight rats (female : male=3:l). The first group of rats served as the untreated controls; the second group received high fluoride(HiF)in their drinking water(100 mg NaF/L); the third group was placed on a low iodine(LI)diet (0.0855 mg I/kg); and the fourth group was exposed to the same concentrations of HiF and LI together. After the animal model was established, the rats were allowed to breed, and 36 offspring rats in each group (female: male=l:l) were randomly selected for the experiments. At 0, 10, 20, 30, 60 and 90 day, the offspring rats were anesthetized and their brain cells prepared for single cell gel electrophoresis (SCGE=comet assay). Ratio of tailing in brain cells of 0, 10, 20, 30, 60 and 90 day-old rats in high fluoride group were 56.11%, 48.74%, 86.74%, 53.84%, 86.58%, 89.09% (average ratio, 70.18%) and the proportion of gradeⅢ damage to brain cells in 20 day-old rats is up to 85.71%. The rate and degree of DNA damage of brain cell in different age rats is higher in the HiF+LI group than in the other experimental groups. And ratio of tailing in brain cells of 0, 10, 20, 30, 60 and 90 day-old rats were 88.25%, 41.23%, 68.22%, 72.62%, 92.61%, 93.91%. These results indicate that DNA strands in the brain cells of rats from 0 day to 90day are adversely affected by exposure to high fluoride, low iodine, and together in combination. The rate and degree of DNA damage in brain cells is higher in the HiF+LI group than in either the HiF or LI group.